Answer:
1. area of a circle = π

2. to find the area of a circle inside a square is the same thing. but if you're trying to find the area of a square WITH a circle inside, you just subtract the area of the circle from the square.
EX: If you have a square that has an area of 24cm and then you have a circle that has an area of 16 cm. To find the area of the square, you just subtract 16 from 25, which would look like 24 - 16 = x
Pi means 3.14, if you want an exact number, on your calculator press the pi button.
r means radius, which is half the diameter.
Diameter is the length of a circle.
just means you square the number. squaring the number basically just means multiply it by itself twice (ex:
is the same as 4 x 4)