Square Area = s2 (s = side length)

Square Area = s2 (s = side length)

• Square Area = s2 (s = side length)

• Rectangle Area = lw (l = length and w = width)

• Triangle Area = ½bh (b = base and h = height)

Be careful when identifying the height of a triangle! The height is NEVER a side of a triangle unless the triangle is RIGHT.

a. A square whose sides have length 8 cm.

• a. A square whose sides have length 8 cm.

b. A rectangle whose length is 5 m and width is 11 m.

• b. A rectangle whose length is 5 m and width is 11 m.

c. A triangle whose side lengths are 3 in, 4 in, and 5 in.

• c. A triangle whose side lengths are 3 in, 4 in, and 5 in.

a. A square with area 256 in2.

• a. A square with area 256 in2.

b. A rectangle with area 345 ft and length 15 ft.

• b. A rectangle with area 345 ft and length 15 ft.

c. A triangle with area 12 mm and a base length of 6 mm.

• c. A triangle with area 12 mm and a base length of 6 mm.

Parallelogram Area = bh (b = base and h = height)

• Parallelogram Area = bh (b = base and h = height)

• Trapezoid Area = ½ h (b1 + b2)

• Rhombus Area = ½d1d2 (d = diagonal)

You can justify the area formula for parallelograms as follows:

Ex 3: Find the area of parallelogram ABCD

Ex 3: Find the area of parallelogram ABCD

Ex 5:The area of a trapezoid is 135 cm2, height is 9, and one bases is 11. Find the other base.

Ex 6: Find the area of the rhombus.

Ex 7: The area of a rhombus is 40 in2 and one of the diagonals is 8 in. Find the other diagonal.