Question

The area of a $△ABC$ is equal to area of square of side length $6$ cm. What is the length of the altitude to $AB$ where $AB=9$ cm?

• A. $18$ cm
• B. $14$ cm
• C. $12$ cm
• D. $8$ cm

Answer 1

The correct option is D $8$ cm

Given that area of $△ABC$ is equal to square of side length $6$ cm

Thus ${\text{(side)}}^2=\frac{1}{2}\times h\times \text{length}AB$

$\Rightarrow 6\times 6=$ $\frac{1}{2}\times 9\times h$
$\Rightarrow h=\frac{36\times 2}{9}=8$ cm

Therefore, the length of the altitude to $AB$ is $8$ cm.