Question 85
In the figures, perimeter of ΔABC = perimeter of ΔPQR. Find the area of ΔABC.
Given, perimeterof ΔABC = perimeter of ΔPQR
∴ Perimeter of ΔPQR=14+6+10=30 cm [∵ perimeter of triangle = sum of all sides]
Now, perimeter of ΔABC=AB+BC+CA
30 = AB + BC + AC
⇒30=AB+5+13⇒30=AB+18⇒AB=30−18=12 cm
Triangle with sides 5, 12, 13 is a right angled triangle.
∴ Area of ΔABC=12×Base×Height
=12×5×12=5×6=30 cm2