Triangles - Area through inradius and circumradius

Rarely Tested

- A = $$\frac{abc}{4R}$$ where R is the circumradius

- A = rs where r is the inradius and s is the semi-perimeter.

- The area of a right angled triangle with inradius r and circumradius R is r(r+2R)

Formula Video


Question 1

In the following figure, ACB is a right-angled triangle. AD is the altitude. Circles are inscribed within the triangle ACD and triangle BCD. P and Q are the centers of the circles. The distance PQ is

The length of AB is 15 m and AC is 20 m

Question 2

An in-circle is drawn inside triangle ABC such that it touches AB,BC,AC at P,Q,R respectively. BQ=5, CQ=6 and inradius = $$\sqrt{\frac{35}{3}}$$. Find the length of the side AB.

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Triangles - Area through inradius and circumradius

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Triangles - Area

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