Question

The triangles shown are similar.

What is the value of x?



A.
9

B.
10

C.
12

D.
15

Answer 1

http://static.k12.com/calms_media/media/1299500_1300000/1299525/1/a506825d97824929139025503c02ad0152987659/141091.jpg

Answer 2

Do you know what scale factor is?

Answer 3

Since the triangle has similar sides, like 3-->6, 4-->8 in order to find X, you would need to find the scale factor.

Answer 4

The scale factor can be found in 8 divided by 4, Or in 6 divided by 3

Answer 5

Both equal 2. which is the scale factor.

Answer 6

Now that we have the scale factor, we can set up the equation, 5(2)=x

Answer 7

It's 5(2) because 2 is the scale factor.

Answer 8

So if they are similar, the corresponding sides are equal to each other via SOME proportion

To find out this factor...we set up the equation setting 2 ratios equal to each other

Take 2 sides of the small triangle *making sure 1 is the corresponding side that we DONT know in the bigger triangle* and set them up as a ratio, and set them equal to the corresponding sides of the larger triangle

\[\large \frac{4}{5} = \frac{8}{x}\]

And then solve for 'x'