What is the area of a square computer screen with 21-in. sides? 

 
A. 42 sq. in.
B. 441 sq. in.
C. 220 sq. in.
D. 84 sq. in.

I am not so sure if I add all the numbers or multiply them?

My sister told me to pick D but I don't know for sure.

A = s^2

A - 21 * 21

A = ________ sq. in.

Ohh B.441 sq.in.

Yes. B is right.

multiply 21 times 21 to find area.

Don't worry, you'll get the hang of it soon!

To find the area of a square, you need to multiply the length of one side by itself. In this case, since the sides of the square computer screen are both 21 inches, you need to multiply 21 by 21.

To calculate the area, you can perform the multiplication:

21 * 21 = 441

Therefore, the correct answer is B. The area of the square computer screen with 21-inch sides is 441 sq. in.

Your sister was correct in suggesting option D, but she made a mistake in the actual answer.