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Area and Pythagoras

The area of a rectangle is length times width. Use the same unit on both sides before you multiply. In a right triangle the square of the hypotenuse equals the sum of the squares of the legs. The hypotenuse is the longest side and lies opposite the right angle. Take the square root at the end, and check that the answer is longer than each leg. Area and length are different quantities and have different units.

A = l \cdot w

rectangle

c = \sqrt{a^2 + b^2}

Pythagoras

Symbols

$l,\ w$	the sides of the rectangle	m
$c$	the hypotenuse	m

Example

A room of 4 m by 3.5 m has area $4 \cdot 3.5 = 14$ m².

Legs 6 and 8: the hypotenuse is $\sqrt{6^2 + 8^2} = 10$ .

Convert to the same unit before you calculate.

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