The formula for the area of a circle can be found by using a parallelogram. explain the way to derive the formula.

the base of the parallelogram, b = half of the circumference of the circle.

half of the circumference of the circle =  πr

therefore, b =  πr

the height of parallelogram, h  =  the radius of the circle

therefore, h = r

area of  a parallelogram = bh

to find the area of the circle, let's substitute  πr  for b and r for h  in the above formula.

area of the circle =  πr * r

area of the circle =  πr²hence, the formula to find area of a circle is  πr²

the multiples of 15 are 15, 30,45, 60, 75, 90, 105, 120, 135, 150, 165, 180, 195,   210, 225, 240, 255, 270, 285, 300, 315, 330, 345, 360, 375,   390, 405, 420, 435, 450, 465, 480, 495, 510, 525, 540, 555, 570, 585, 600, 615, 630, 645, 660, 675, 690, 705, 720, and 735.

the factors of 15 are 1, 3, 5, and 15.

hope that , fam!

-une, your fren : )