Intermediate Algebra for College Students (7th Edition)

Published by Pearson
ISBN 10: 0-13417-894-7
ISBN 13: 978-0-13417-894-3

Chapter 7 - Section 7.5 - Multiplying with More Than One Term and Rationalizing Denominators - Exercise Set - Page 551: 119

Answer

Perimeter $=8\sqrt {2}$ inches. Area $=7$ square inches.

Work Step by Step

Length of the rectangle $l=\sqrt {8}+1$ inches. Width of the rectangle $w=\sqrt {8}-1$ inches. Perimeter: $\Rightarrow P=2l+2w$ Substitute values. $\Rightarrow P=2(\sqrt {8}+1)+2(\sqrt {8}-1)$. Clear the parentheses. $\Rightarrow P=2\sqrt {8}+2+2\sqrt {8}-2$. Simplify. $\Rightarrow P=4\sqrt {8}$. Factor the radicands. $\Rightarrow P=4\sqrt {2^2\cdot 2}$. Simplify. $\Rightarrow P=4\cdot 2\sqrt {2}$. Simplify. $\Rightarrow P=8\sqrt {2}$. Hence, the perimeter is $8\sqrt {2}$ inches. Area : $\Rightarrow A=lw$ Substitute values. $\Rightarrow A=(\sqrt {8}+1)(\sqrt {8}-1)$ Use the special formula $(A+B)(A-B)=A^2-B^2$. $\Rightarrow A=[(\sqrt {8})^2-(1)^2]$ Clear the parentheses. $\Rightarrow A=8-1$ Simplify. $\Rightarrow A=7$ Hence, the area is $7$ square inches.
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