Trigonometric Equations Question 222
Question: The radius of the in circle of triangle when sides are 18, 24 and 30 cms is
[Pb. CET 2004]
Options:
A) 2 cm
B) 4 cm
C) 6 cm
D) 9 cm
Show Answer
Answer:
Correct Answer: C
Solution:
- $ r=\frac{\text{Area of triangle}}{s}=\frac{\Delta }{s} $ $ s=\frac{a+b+c}{2}=\frac{18+24+30}{2} $ , $ s=36 $ $ \Delta =\sqrt{s(s-a),(s-b),(s-c)} $ $ \Delta =\sqrt{36,(36-18),(36-24),(36-30)} $ $ \Delta =\sqrt{36\times 18\times 12\times 6}=216 $ So, radius of in circle = $ \frac{216}{36}=6cm $ .
BETA
