Question

The base of a triangle is $15cm$ and its height is $12cm$. The height of another triangle of double the area and the base of which is $20cm$, is given by

• A. $9cm$
• B. $18cm$
• C. $8cm$
• D. $12.5cm$

Answer 1

The correct option is B $18cm$

Given that:

Area of $1^{st}$ triangle $\left(A\right)=\frac{1}{2}\times 15\times 12=90c{m}^2$
So,

Area of $2^{nd}$ triangle $=180c{m}^2$
Area of $2^{nd}$ triangle $=\frac{1}{2}\times 20\times Height$
$180=10\times Height$
$Height=18cm$