How do you work out the perimeter and the area?

Answer 1

This all depends on the shape you are given! Let's work on each part of the terms:

1. Perimeter - You add up all the sides of the shapes for some closed unrounded shape. If the shapes are rounded or ovalish, then you need to use this form to work out the problem: C = 2πr or apply Euler's formula to work out the circumference.
2. Area - For some shapes with closed straight edges, you multiply the sides of the shapes. Though, for other shapes, like pentagon, you need to multiply the length of the apothem by the side of the shape. If you work on the ellipse or ovalish or round shapes, like circle, then you need to use some of these general forms:

• 2π/√(4AC - B²) coming from Ax² + Bxy + C² = 1. This is the area of the ellipse.
• A = πr², the area of the circle!
• Other formulas for shapes with "curly" edges are unknown. The only way to work out the area is to apply integration in calculus.