Question

The base of a triangle is nine centimeters longer than the perpendicular height. If the area of the triangle is 180 square centimeters, what is the length of the base, in centimeters?

Answer 1

Answer:

The base is 24 cm long.

Step-by-step explanation:

Equations

Let's call

b= base of the triangle

h=height of the triangle

The base is 9 cm longer than the height, thus:

b = h + 9

The area of the triangle is:

$\displaystyle A=\frac{bh}{2}$

$\displaystyle A=\frac{(h+9)h}{2}$

And its value is 180:

$\displaystyle \frac{(h+9)h}{2}=180$

Multiplying by 2:

$(h+9)h=360$

Operating:

$h^2+9h-360=0$

Factoring:

$(h-15)(h+24)=0$

The only valid positive solution is:

h = 15 cm

And b = h + 9 = 24

b = 24 cm

The base is 24 cm long.