CPM Homework Help : AC Problem 7-17

The figures below are similar (meaning they have the same shape). Use the information given about the lengths of the sides to solve for $x$ and $y$ .

A quadrilateral with sides labeled, starting at the top and going clockwise, as follows: y, 9, 12 and 6.

A larger quadrilateral, in the same orientation, with sides labeled, starting at the top and going clockwise, as follows: 15, x, 20, and 10.

Hint:

Use proportions to solve for $x$ and $y$ .

Step 1:

$\frac{6}{10}=\frac{\it y}{15}$

Step 2:

$10y=90$

Partial Answer:

$y=9$