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

For this question. this demostration is new for me. i found it in internet and now i can explain it to you.1) divide the circle in many congruent sectors (like spliting a pizza or a cake y many slices).2) now imagine that you separate all the slices and align them one next to each other. align them intercalating the position: peak down, peak up, peak down, peak up, 3) that mains a kind of chain, in form of paralellogram but with bumpsnow, you can imagine that if you slice the circle in so many pieces (tens, hundreeds, thousands, the bumps will flaten and, at the limit (as the number of slices approaches infinity), the figure constructed with the slices will be a parallelogram.4) in that parallelogran, the larger side will have a measure equal to the half of the perimeter of the circle, this is, 2πr / 2 = πr.5) the shorter side will measure r.6) the area of a parallelogram is side × side, so for this parallelogram it will be πr×r = πr², which is indeed the equation for the are of a circle.we have, then, shown how the formula of the area of a parallelogram can be used to derive the formula of the area of a circle.

The answers are 20,30,80,180,960,890,1230,4560. on the first row