Question

In the following figure a circle is inscribed inside a triangle such that all the three sides of triangle are tangent to circle so OD, OE and OF are perpendicular to AB, AC and BC respectively, Now we know that area of triangle = ½ × base of the triangle × height of the triangle

1. If in above figure radius of the circle is r cm and perimeter of triangle is p cm then find the area of triangle ABC in terms of r and p.
A) ½ × pr cm²
B) pr cm²
C) (3/2)pr cm²
D) 2pr cm²​

2. If in above figure AB = 5 cm, BC = 6 cm and CA = 7 cm then find the radius of circle inscribed?
A) (5/9) √6 cm²
B) (6/9) √6 cm²
C) (4/9) √6 cm²
D) (7/9) √6 cm²

Answer 1

area of triangle= 1/2× r×p/3×3

area of triangle= 1/2pr