Similar Triangles

Similar Triangles

Scale Factors, Proportions, Indirect Measurement

Open Ended

What do similar triangles have in common?

It's like the Super Bowl halftime show was meant to be with this unit

Multiple Choice

Find x.

• 54/7

• 56/3

• 11

• 21/2

Multiple Choice

Solve for X

• 7.5

• 4.8

• 13.33

• 5

A scale factor is a multiplier. Because all sides of similar triangles are proportional, they all must be multiplied by the same number. If you can observe a pair of sides, you can often calculate other missing sides easily with the S.F.

Multiple Choice

What is the length of EF?

• 12

• 18

• 24

• 28

Sometimes the scale factor isn't obvious, or it's annoying to apply. This one is 1.25, but there's a better way.

Make a proportion where each fraction comes from corresponding sides.

Cross Multiply

Solve for x. This process is called indirect measurement. It works for shapes that are proportional, like similar triangles.

You're about to find X and Y, so get equipped with some scrap paper.

Multiple Choice

What is the value of x?

• 10.5

• 4.33

Multiple Choice

What is the value of y?

• 5.33

• 12

• 6

• 5.66