SME
Grade 10 Math
Geometry
Geometry basics: points, lines, segments, angles and constructions
Main lesson
Midpoint with an unknown
Use this for “M is the midpoint of AC, AM = 3x + 1 and MC = 5x − 7. Find x, AM and AC.”
Angle addition
Use this for “m∠AOB = 38° and m∠BOC = 47°. Find m∠AOC.”
Construct a perpendicular bisector
Use this for “AB is 6 cm and the compass is open to 4 cm. How far above AB do the arcs cross?”
Construct a perpendicular bisector
Use this for “What is the next step in constructing the perpendicular bisector of AB?”
Bisect an angle
Use this for “Put the steps for bisecting ∠AOB with a compass in order.”
What the angle bisector construction guarantees
Use this for “After bisecting ∠AOB with a compass, which statements must be true?”
Find the center of a circle
Use this for “How can you find the center of a circle with a compass and straightedge?”
Reasoning and proof: conditional statements and two-column proofs
Main lesson
Triangle angle sum and exterior angle
Use this for “Side BC is extended to D. m∠A = 52° and m∠B = 71°. Find m∠ACD and m∠ACB.”
Base angles of an isosceles triangle
Use this for “Given AB = AC, prove ∠B = ∠C” and “An isosceles triangle has a 40° vertex angle. What are its base angles?”
Conditional, converse, inverse, contrapositive
Use this for “Write the converse of ‘If two angles are vertical, then they are congruent.’ Is it true?”
Inductive or deductive?
Use this for “Is this conclusion reached by inductive or deductive reasoning?”
Reasons in an algebraic proof
Use this for “Solve 2(x − 3) = 14 and give a reason for each step.”
Parallel and perpendicular lines: transversals and proofs
Main lesson
Alternate interior angles
Use this for “ℓ ∥ m and m∠1 = 118°. Find m∠3 and m∠6.”
Same-side interior angles
Use this for “ℓ ∥ m and m∠4 = 73°. Find m∠6.”
Are the lines parallel?
Use this for “m∠1 = 81° and m∠5 = 79°. Are lines ℓ and m parallel?”
Angle expressions
Use this for “ℓ ∥ m, corresponding angles are (4x + 12)° and (2x + 50)°. Find x and the angle.”
A parallel line through a point
Use this for “Write the equation of the line parallel to y = 3x − 4 through (2, 7).”
A perpendicular line through a point
Use this for “Write the equation of the line perpendicular to y = 2x + 1 through (4, 3).”
Why a triangle’s angles add to 180°
Use this for “Prove that the angles of a triangle add to 180°.”
Rigid motions, compositions and symmetry
Main lesson
A glide reflection
Use this for “Translate A(1, 2) 5 units right, then reflect it across the x-axis.”
Rotating about a point
Use this for “Rotate A(6, 2) 90° counterclockwise about the point (1, 1).”
Reflecting across y = x or y = −x
Use this for “Reflect A(4, 1) across the line y = x” or “across y = −x.”
Symmetry of a rectangle
Use this for “Which rotations carry a 6 by 4 rectangle onto itself? How many lines of symmetry does it have?”
Which motion is the rule?
Use this for “Is (x, y) → (2x, 2y) a rigid motion? Which move is (x, y) → (−y, x)?”
Congruent triangles: SSS, SAS, ASA, AAS and HL
Relationships within triangles: bisectors, medians, midsegments and inequalities
Main lesson
Medians and the centroid
Use this for “The median AD is 12. How long are AG and GD?”
The incircle of a right triangle
Use this for “A right triangle has legs 9 and 12. Find the radius of the circle inside it.”
The circle through the corners of a right triangle
Use this for “A right triangle has legs 5 and 12. Find the radius of the circle through its corners.”
The triangle inequality
Use this for “Two sides of a triangle are 7 and 11. What lengths can the third side be?”
Which center?
Use this for “Which point of a triangle is the same distance from all three sides?”
Which angle is largest?
Use this for “A triangle has sides 5, 7 and 9. Which angle is the largest? The smallest?”
Quadrilaterals and other polygons: angle sums and properties
Main lesson
Angles of a parallelogram
Use this for “In parallelogram ABCD, m∠A = 58°. Find m∠B and m∠C.”
Rectangle and its diagonals
Use this for “A rectangle is 12 by 5. How long is each diagonal?”
Rhombus from its diagonals
Use this for “A rhombus has diagonals 12 and 16. Find its side and its area.”
Trapezoid midsegment and area
Use this for “A trapezoid has bases 9 and 15 and height 5. Find its midsegment and area.”
Kite
Use this for “A kite’s diagonals cross at O; BD = 12, OA = 8 and OC = 4.5. How long are its sides?”
Area of a regular polygon
Use this for “A regular hexagon has sides of 4 cm. Find its apothem and its area.”
Name it exactly
Use this for “A parallelogram has perpendicular diagonals. What is the most exact name for it?”
Similarity: dilations and similar triangles
Main lesson
Dilation from a center
Use this for “Dilate an 8 by 6 rectangle by a scale factor of 0.5 from the point O.”
The side-splitter theorem
Use this for “DE ∥ BC, AD = 6, DB = 4 and AE = 9. Find EC.”
The parallel side of a split triangle
Use this for “DE ∥ BC, AD = 3, AB = 12 and BC = 20. How long is DE?”
Is DE parallel to BC?
Use this for “D is on AB and E is on AC; AD = 4, DB = 6, AE = 6 and EC = 9. Is DE parallel to BC?”
Scale factor, perimeter and area
Use this for “A 3 by 4 rectangle is enlarged by 2.5. What are the new perimeter and area?”
Altitude to the hypotenuse
Use this for “The altitude to the hypotenuse cuts it into 4 and 9. How long is the altitude?”
Similar, and by which test?
Use this for “Which pairs of triangles must be similar, and why?”
The Pythagorean theorem's converse and special right triangles
Right-triangle trigonometry: sine, cosine and tangent
Main lesson
Find a side from an angle
Use this for “A 7.5 m ladder leans at 38° to the ground. How high up the wall does it reach?”
Find an angle from two sides
Use this for “A ramp rises 1.5 m over a run of 6 m. What angle does it make with the ground?”
Angle of elevation
Use this for “Standing 36 m from a tree, you look up 28° to its top. How tall is the tree?”
Sine and cosine of complementary angles
Use this for “sin 28° is about 0.4695. Which cosine is equal to it?”
The law of sines and the law of cosines
Main lesson
Two sides and the angle between them
Use this for “b = 7, c = 10 and A = 50°. Find a.”
Three sides: find an angle
Use this for “The sides are 5, 7 and 9. Find the largest angle.”
The ambiguous case (SSA)
Use this for “A = 30°, a = 6 and b = 10. How many triangles fit, and what is B?”
Area from two sides and the angle between them
Use this for “Two sides of a triangle are 8 and 11 with a 40° angle between them. Find its area.”
Coordinate geometry: distance, midpoint, partitioning a segment and coordinate proofs
Main lesson
The midpoint of a segment
Use this for “Find the midpoint of the segment from (−4, 3) to (8, −5)” or “M is the midpoint; find the other end.”
The point that splits a segment in a ratio
Use this for “Find the point P on AB, A(−2, 1) and B(10, 7), with AP:PB = 1:2.”
Prove a parallelogram with slopes
Use this for “Show that A(−3, −1), B(−1, 3), C(5, 4), D(3, 0) is a parallelogram.”
Prove a right triangle with slopes
Use this for “Is the triangle A(−1, 1), B(1, 5), C(5, 3) a right triangle?”
Perimeter and area on the grid
Use this for “Find the perimeter and area of the triangle A(0, 0), B(6, 0), C(3, 4).”
Circles: arcs, chords, tangents and inscribed angles
Main lesson
The angle in a semicircle
Use this for “AB is a diameter and m∠PAB = 34°. Find m∠PBA.”
A tangent and its radius
Use this for “The radius is 8 and the tangent from P is 15. How far is P from the center?”
Two chords crossing
Use this for “Chords AB and CD cross at E; AE = 6, EB = 4 and CE = 3. Find ED.”
Two secants from a point
Use this for “From P, PA = 3 and PB = 10 on one secant, PC = 5 on the other. Find PD.”
A tangent and a secant from a point
Use this for “From P, PA = 4 and PB = 16 on a secant. How long is the tangent PT?”
Opposite angles of an inscribed quadrilateral
Use this for “ABCD is inscribed in a circle and m∠A = 84°. Find m∠C.”
Angles from arcs
Use this for “Two chords cross inside a circle, cutting off arcs of 70° and 110°. Find the angle.”
Equations of circles
Arc length, sector area and radian measure
Surface area and volume of solids, cross sections and Cavalieri's principle
Main lesson
Surface area of a cylinder
Use this for “Find the surface area of a can with radius 4 cm and height 7 cm.”
Volume of a cone
Use this for “A cone has radius 3 cm and height 4 cm. Find its volume.”
Surface area of a cone
Use this for “A cone has radius 3 cm and height 4 cm. Find its slant height and surface area.”
Volume of a pyramid
Use this for “A square pyramid has base side 6 cm and height 10 cm. Find its volume.”
Surface area and volume of a sphere
Use this for “A ball has radius 5 cm. Find its surface area and volume.”
A level cut of a cone
Use this for “A cone has radius 6 cm and height 9 cm. What is the area of a level cut 3 cm up?”
Surface area of a pyramid
Use this for “A square pyramid has base side 6 cm and height 4 cm. Find its slant height and surface area.”
What shape is the cut?
Use this for “A plane cuts a cube through three corners. What shape is the cross section?”
Turn a shape: which solid?
Use this for “A right triangle is turned about one leg. What solid does it sweep out?”
Modeling with geometry: density, design and optimization
Main lesson
Mass of a ball from its density
Use this for “A steel ball has radius 1.5 cm and steel is 7.8 g/cm³. Find its mass.”
Mass of a cone from its density
Use this for “A solid aluminum cone (2.7 g/cm³) has radius 3 cm and height 4 cm. Find its mass.”
Population density
Use this for “45,000 people live within 3 km of a town’s center. How many people per km²?”
Designing a can with the least material
Use this for “A can must hold 500 cm³. Which radius uses the least metal?”
The most area for a fixed perimeter
Use this for “40 m of fence makes a rectangular pen. Which sides give the most area?”
Sample spaces, the addition rule, permutations and combinations
Main lesson
Mutually exclusive events
Use this for “P(red) = 0.25 and P(blue) = 0.40 for one marble. Find P(red or blue).”
The complement rule
Use this for “The chance of rain is 0.35. What is the chance of no rain?”
Neither event
Use this for “Of 40 students, 22 play soccer, 15 basketball and 8 both. How many play neither, and what is the chance of neither?”
Listing equally likely outcomes
Use this for “Three coins are tossed. What is the chance of exactly two heads?”
Permutations: order matters
Use this for “In how many ways can 8 runners take gold, silver and bronze?”
Combinations: order doesn’t matter
Use this for “In how many ways can a committee of 3 be chosen from 8 people?”
Probability with combinations
Use this for “3 students are picked at random from 5 girls and 4 boys. What is the chance all 3 are girls? Exactly 2?”
Conditional probability and independence
Main lesson
A tree with conditional branches
Use this for “P(Rain) = 0.3, P(Late | Rain) = 0.4, P(Late | Dry) = 0.1. Find P(Late) and P(Rain | Late).”
Independent events: three stages
Use this for “Three trains are on time with chances 0.9, 0.8 and 0.7. What is the chance all three are? That at least one is late?”
Two draws without replacement
Use this for “A bag has 5 red and 3 blue marbles. Two are drawn without putting the first back. Find P(red, then red).”
Conditional probability on a Venn diagram
Use this for “Of 60 students, 25 drink juice, 30 milk and 10 both. What fraction of the juice drinkers drink milk?”