Question

The area of triangle $PQR$ is $100c{m}^2$ (figure). If altitude $QT$ is $10cm$, then its base $PR$ is:

• A. $\text{20 cm}$
• B. $\text{10 cm}$
• C. $\text{15 cm}$
• D. $\text{5 cm}$

Answer 1

The correct option is A $\text{20 cm}$

We know that,

Area of triangle $=\frac{1}{2}\times \text{base}\times \text{height}$
From the given details, we have,
Area of triangle $PQR=100c{m}^2$
Height of the triangle (altitude) $=10cm$
Therefore,

$100=\frac{1}{2}\times PR\times 10$
$PR=\frac{100\times 2}{10}$
$PR=20cm$