Question

What is the value of x?

Enter your answer in the box.

Answer 1

x=28

Explanation:

We can use proportions to solve this problem. Put the side of the small triangle over the side of the large triangle.

x 42

------ = ----------

x+10 42+15

x 42

------ = ----------

x+10 57

Solve using cross products

57x = 42(x+10)

Distribute

57x = 42x+420

Subtract 42x from each side

57x-42x = 42x-42x+420

15x = 420

Divide by 15

15x/15 = 420/15

x=28