Question

The area of the triangle whose two sides are 18cm and 10cm, respectively and the perimeter equal to 42 cm is $21\sqrt{11}$Sq cm.

• A. True
• B. False

Answer 1

The correct option is A True

Perimeter = 42
a+b+c=42
18+10+c=42
c=42-28=14 cm
Semi perimeter, s=42/2= 21cm
Using Heron’s formula: A=$\sqrt{21(21-18)(21-10)(21-14)}=\sqrt{21\times 3\times 11\times 7}$=21$\sqrt{11}$ sq cm.