Lesson 2: Area - Estimation Example 1


EXAMPLE 1

Estimate the area of the circle, using the underestimation/overestimation method. Each square represents 1 m2.



Solution


Step 1: Underestimate the area of the circle.

There are 35 full squares inside the circle. The underestimation is 35 m2.



Step 2: Overestimate the area of the circle.

There are 67 touching the circle. The overestimation is 67 m2.



Step 3: Calculate the average

\(\begin{align} \text{A}_{\text{estimate}}&=\frac{\left(\text{under-estimate+over-estimate}\right)}{2} \\ \\ &=\frac{\left(35\,\text{m}^{2}+67\,\text{m}^2\right)}{2} \\ \\ &=51\,\text{m}^2 \\ \end{align}\)

The area of the circle is about 51 m2.


2014 © Alberta Distance Learning Centre