# Multiplication Worksheets - Page 3

Multiplication Worksheets
• Page 3
21.
The height of the triangle is 10 times the base $b$ in a right triangle. Find the area of the triangle.
 a. 5$b$ square units b. 15$b$2 square units c. 10$b$2 square units d. 5$b$2 square units

#### Solution:

Height of the triangle is 10b units.

Area of a triangle = 1 / 2 x base x height
[Write the formula.]

= 12 × b × 10b
[Substitute the values.]

= 5b2
[Simplify.]

Area of the right triangle is 5b2 square units.

22.
Find the area of the rectangle.

 a. ($y$2 - 4$y$) square units b. (4$y$2 - 4$y$) square units c. ($y$2 - 4) square units d. (4$y$2 - $y$) square units

#### Solution:

2y and (2y - 2) are the sides of the rectangle.

Area of the rectangle = Length x Width
[Write the formula.]

= 2y(2y - 2)
[Substitute the values.]

= 2y(2y) - 2(2y)
[Use distributive property.]

= 4y2 - 4y
[Multiply.]

Area of the rectangle is (4y2 - 4y) square units.