One of the most fundamental truths of (Euclidean) geometry is that the ratio of the circumference to the diameter of any circle is a constant, and that constant is called pi (denoted by π π). Let C be the (length of the) circumference of a circle, and let d be its diameter. Then, we must have: C d = π C d = π
4x -2y = 60
4x -3y = 26
(-) (+) (-)
__________
1y = 34
y = 34
To find x
4x -2y = 60
4x -(2)(34) = 60
4x -68 = 60
4x = 60 + 68
4x = 128
x = 32
Answer:
x=32 ; y=34
Answer: It represents the area of the two circular sides ("lids")
Explanation:
Imagine you made a cylinder out of 3 pieces of paper. The cylinder can be decomposed into two circular shapes (radius r) and one rectangular piece with two side lengths: one is "h", the other has to be long enough to go around each of the disks, so it has to be 2*pi*r long.
So the term 2*pi*r*h is the area of the rectangular piece and pi*r^2 is the area of each of the "lids" Since there are two of those, the term 2*pi*r^2 represents the area of the bottom and top lids.
