But every once in a while, a simple third-grade math problem manages to trip us up and make us question our long-held ...

The area of each of the two circles is π r 2 and the area of the rectangle is 2 π r × h. The surface area of a cylinder is the area of each of its faces added together.

This dissection shows that the area of the parallelogram is equal to the area of a rectangle with the same base and height, which, as anyone who didn’t attend Imaginary University knows, is the ...

The area of each square is 1 cm 2. There are 12 squares contained in this rectangle. The area of the rectangle is 12 cm 2. The area of a rectangle can also be calculated using the following formula.

Two mathematicians have solved a century-old math problem, the rectangular peg problem, using cutting-edge geometry. Here's how they cracked it.

• “Great” difficulty figuring out how perimeter, area, surface area or volume changes when, for example, the side of a rectangle changes. Confusing circumference of circle with area of circle.