Question

3. The area A of a triangle varies jointly as the base b and the altitude h of the triangle. If the area

of a triangle is 70 cm2 when the base is 14 cm and the altitude is 10 cm, find the area if the base is
8 cm and the altitude is 12 cm.​

Answer 1

48cm²

Explanation:

If the area A of a triangle varies jointly as the base b and the altitude h of the triangle, this is expressed as;

A = kbh

k is the constant of proportionality

If A = 70cm², b = 14cm and h = 10cm

Substitute

70 = k(14)(10)

70 = 140k

k = 70/140

k = 0.5

To get the area if base is 8 cm and the altitude is 12 cm;

A = 0.5*8*12

A = ​48cm²

Hence the required area is 48cm²