Question

What is the circum radius for triangle sides 9 cm, 40 cm and 41 cm.

• A. 9 cm
• B. 20.5 cm
• C. 21 cm
• D. 22 cm

Answer 1

The correct option is A 9 cm

The altitude of a triangle with side a, b, c are:

$[\frac{\sqrt{\left(\right(b+a{)}^2-c^2\left)\right(c^2-(b-a{)}^2)}}{2a},\frac{\sqrt{\left(\right(b+c{)}^2-a^2\left)\right(a^2-(c-b{)}^2)}}{2a},\frac{\sqrt{\left(\right(b+c{)}^2-a^2\left)\right(a^2-(b-c{)}^2)}}{2a}]$

Put $a=a$, $b=40$, $c=41$

$\therefore [40,9,\frac{360}{41}]$

$\therefore$ circum radius $=9$cm.