Find the side $ a $ of a rectangle if side $b = 9$ and diagonal $d = 19$.
Answer
$a = 2 \sqrt{ 70 }$
Explanation
To find side $ a $ use Pythagorean Theorem:
$$ a^2 + b^2 = d^2 $$After substituting $ b = 9 $ and $ d = 19 $ we have:
$$ a ^ {\,2} + 9^2 = 19^2 $$ $$ a ^ {\,2} = 19^2 - 9^2 $$ $$ a ^ {\,2} = 361 - 81 $$ $$ a ^ {\,2} = 280 $$ $$ a = \sqrt{ 280 } $$$$ a = 2 \sqrt{ 70 } $$This page was created using
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