JEE Main202116 Mar 2021Evening ShiftMathematicsProperties of TrianglesActual
In ΔABC , the lengths of sides A C and A B are 12 cm and 5 cm , respectively. If the area of ∆ ABC is 30 cm 2 and R and r are respectively the radii of circumcircle and incircle of ΔABC , then the value of 2 R + r ( in cm ) is equal to ______ .
Correct answer
0
Step-by-step solution
Δ = 1 2 · 5 · 12 · sinA = 30 sinA = 1 A = 90 ° ⇒ BC = 13 BC = 2 R = 13 r = Δ S = 30 15 = 2 2 R + r = 15