Question

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

• A. $15cm$
• B. $20cm$
• C. $10cm$
• D. $5cm$

Answer 1

The correct option is B $20cm$

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,

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

$PR=\frac{100\times 2}{10}$

$PR=\frac{200}{10}$

$PR=20cm$