Finding the Area of ​​a Rectangle: Formula and Example

Rectangle is a geometric figure; a quadrilateral all of whose angles are right angles (equal to 90 degrees).

The formula for calculating the area of ​​a rectangle

1. By length and width

S = a ⋅ b

The area of ​​the rectangle (S) is found by multiplying its length and width, in other words, two adjacent sides.

2. Along the diagonals and the angle between them

The area of ​​the rectangle (S) is equal to half the square of the diagonal multiplied by the sine of the angle between the diagonals.

Note: the diagonals of the rectangle are equal.

Example of a problem

Find the area of ​​a rectangle if its length is 6 cm and its width is 4 cm.

Decision:

S=6 cm ⋅ 4 cm=24 cm².