Question

The angle of a triangle are in the ratio $1:4:5$, Find the angles of the triangle.

Answer 1

Let the angles of a triangle $x:4x:5x$

$\Rightarrow x+4x+5x={180}^{\circ }$ by angle sum property of a triangle.

$\Rightarrow 10x={180}^{\circ }$

$\therefore x=\frac{{180}^{\circ }}{10}={18}^{\circ }$

Hence $x={18}^{\circ }$

$4x=4\times {18}^{\circ }={72}^{\circ }$

and $5x=5\times {18}^{\circ }={90}^{\circ }$

The angles are ${18}^{\circ },{72}^{\circ }$ and ${90}^{\circ }$