If given area and length of a rectangle, how do I find the perimeter?

Use the Pythagorean theorem to find the sides and then find the perimeter.

For the perimeter, add the four sides together and simplify. For the area, multiply the length by the width.

Let x = the width. Then the length is 2x - 7. The perimeter is twice the width plus twice the length: 64 = (2x) + 2(2x - 7) =...

The perimeter equals the side length times the number of sides. In this case, multiply 21 by 9 and you will get a perimeter of 189.

Such a rectangle would have its sides and diagonal in the ratio of 2:1:√5 (per the Pythagorean theorem). The ratio of √5 to the diagonal (20) is equal to the...

A=area, L=length of 1 equal side, b=base, θ=HALF of angle between 2 equal sides. Split the triangle in half down the middle. The middle line is h, the height. Analyze...

Use the Pythagorean Theorem to find the other side. Then multiply the length by the width.

You can't. With any given perimeter, an infinite number of length-width combinations would be possible.

Let B equal the breadth. Then 2B equals the length. Write an equation in B, stating that the perimeter is equal to twice the breadth plus twice the length. Solve...

Double the width, and subtract that from the perimeter. Then divide that number by two, which gives you the length of the rectangle. Then, multiply the result by the width...