Question

lesson 2: drilling for understanding

1. find the area of the following shapes. be sure to include units.

a. 8 cm
7 cm
c. 3.6 mm
12.5 mm

Explanation:

Step1: Recall triangle - area formula

The formula for the area of a triangle is $A=\frac{1}{2}bh$, where $b$ is the base and $h$ is the height. For the triangle with $b = 7$ cm and $h=8$ cm.
$A=\frac{1}{2}\times7\times8$

Step2: Calculate triangle area

$A=\frac{1}{2}\times56 = 28$ cm²

Step3: Recall rectangle - area formula

The formula for the area of a rectangle is $A = lw$, where $l$ is the length and $w$ is the width. For the rectangle with $l = 12.5$ mm and $w = 3.6$ mm.
$A=12.5\times3.6$

Step4: Calculate rectangle area

$A = 45$ mm²

Answer:

a. The area of the triangle is 28 cm².
c. The area of the rectangle is 45 mm².