Given:
The function for size of a square frame is

where, x is the side length of the picture.
The function for the price in dollars for the frame is

To find:
The single function for the price of a picture with an edge length of x.
Solution:
We know that, for a picture with an edge length of x.
Size of a square frame = f(x)
Price in dollars for the frame = p(x)
Single function for the price of a picture with an edge length of x is

![[\because f(x)=x+2]](https://tex.z-dn.net/?f=%5B%5Cbecause%20f%28x%29%3Dx%2B2%5D)
![[\because p(x)=3x]](https://tex.z-dn.net/?f=%5B%5Cbecause%20p%28x%29%3D3x%5D)
Let the name of this function is c(x). So,

Therefore, the required function is
.
If you find a wrong thing on answer respond me
Hi there! The answer is 100πcm^2
The radius of a circle can be found by dividing the diameter by 2. In other words : the radius is half of the diameter.
Therefore, the radius of a circle with a diameter of 20 cm is 10 cm.
The exact area of a circle can be found using the following formula:

In order to find our answer, we need to plug in the data from the question.

Hence, the answer is 100πcm^2.
17. Area of triangle: 1/2bh
1/2 * 12 * 15
1/2 * 180
=90 cm^2
18. Area of trapezoid: 1/2 h (b1 + b2)
1/2 * 8 ( 12 + 15.4)
4 * 27.4
= 109.6 cm^2