Question

In a triangle ABC, a : b : c = 4 : 5 : 6. The ratio of the radius of the circumcircle to that of the incircle is –

• A. 15/4
• B. 11/5
• C. 16/7
• D. 16/3

Answer 1

Answer: (C)

16/7

Answer 2

Let = $\frac { b } { 5 }$ = $\frac { \mathrm { c } } { 6 }$ = k

R = $\frac { \mathrm { abc } } { 4 \Delta }$ and r =

⇒ $\frac { \mathrm { R } } { \mathrm { r } }$ = × $\frac { \mathrm { s } } { \Delta }$ =

= $\frac { s ~ a b c } { 4 s ( s - a ) ( s - b ) ( s - c ) }$

=

= $\frac { 5 \times 6 \times 8 } { 7 \times 5 \times 3 }$ =$\frac { 16 } { 7 }$.