U7 Formulas for Area of Circles and Polygons

Front

What is the formula for the area of a rectangle?

Back

A = lw, where l is the length and w is the width.

Front

What is the formula for the area of a triangle?

Back

A = 1/2(bh), where b is the base and h is the height.

Front

What is the formula for the area of a kite?

Back

A = \frac{d_1 d_2}{2}, where d_1 and d_2 are the lengths of the diagonals.

Front

What is the formula for the area of a trapezoid?

Back

A = \frac{1}{2}(h)(b_1 + b_2), where h is the height and b_1 and b_2 are the lengths of the two bases.

Front

What is the formula for the area of a circle?

Back

A = \pi r^2, where r is the radius.

Front

What is the formula for the area of a square?

Back

A = s^2, where s is the length of a side.

Front

What is the relationship between the radius and diameter of a circle?

Back

The diameter is twice the radius: d = 2r.

Front

How do you find the height of a triangle if you know the area and base?

Back

Use the formula A = 1/2(bh) and solve for h: h = \frac{2A}{b}.

Front

What is the area of a rectangle with length 5 cm and width 3 cm?

Back

A = lw = 5 cm * 3 cm = 15 cm².

Front

What is the area of a triangle with base 4 cm and height 6 cm?

Back

A = 1/2(bh) = 1/2(4 cm * 6 cm) = 12 cm².