ABC is an isosceles triangle inscribed in a circle. If AB = AC = 12$$\sqrt 5 $$ and BC = 24 cm then radius of circle is:
A. 10 cm
B. 15 cm
C. 12 cm
D. 14 cm
Answer: Option B
Solution(By Examveda Team)
$$\eqalign{ & {R_2} = \frac{{abc}}{{4\vartriangle }} \cr & \vartriangle = \sqrt {S\left( {s - a} \right)\left( {s - b} \right)\left( {s - c} \right)} \cr} $$
$$ = \sqrt {12\left( {\sqrt 5 + 1} \right)\left( {12} \right) \times 12 \times 12\left( {\sqrt 5 - 1} \right)} $$
where a = 12$$\sqrt 5 $$ , b = 12$$\sqrt 5 $$ & c = 24
$$\eqalign{ & S = \frac{{a + b + c}}{2} \cr & S = \frac{{24\sqrt 5 + 24}}{2} \cr & S = 12\left( {\sqrt 5 + 1} \right) \cr & {R_2} = \frac{{12\sqrt 5 \times 12\sqrt 5 \times 24}}{{4 \times 12 \times 12 \times 2}} \cr & {R_2} = \frac{{30}}{2} \cr & {R_2} = 15\,{\text{cm}} \cr} $$
Related Questions on Triangles
If ABC and PQR are similar triangles in which ∠A = 47° and ∠Q = 83°, then ∠C is:
A. 50°
B. 70°
C. 60°
D. 80°
In the following figure which of the following statements is true?
A. AB = BD
B. AC = CD
C. BC + CD
D. AD < Cd
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