SME
Grade 10 Math
Similarity: dilations and similar triangles
The main lesson, then each kind of problem it solves.
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?”