Question

The triangles are similar. Find the value of x.

Answer 1

Answer:

Explanation:

You just need to find the ratio of lengths of one of the sides and apply it to the unknown side:

72

24

=

3

This means that the triangle on the right has sides that are 3 times the length of the smaller triangle.

x

7

=

3

x

=

21

Answer link

Answer 2

Answer:

x = 36

Step-by-step explanation:

Remark

This can be done as a proportion. A proportion consists of 2 ratios which means it has 4 parts. If you know three of them, you can solve for the 4th.

We can use the following proportion

42/14 = x / 12    Notice that both ratios have tops and bottoms that use corresponding parts. Cross Multiply

14*x = 42 * 12            Combine the right

14x  = 504                 Divide by 14

x = 504/14

x = 36