Question

The angles of a pentagon are $(3x+4{)}^0,(x+20{)}^0,(3x-5{)}^0,(2x+10{)}^0$ and $(4x-9{)}^0$. Find $x$.

• A. ${52}^{\circ }$
• B. ${60}^{\circ }$
• C. ${40}^{\circ }$
• D. ${18}^{\circ }$

Answer 1

Answer: (C)

${40}^{\circ }$

$\text{Sum of the angles of pentagon}={180}^0(5-2)={540}^0$
$\therefore 3x+4+x+20+3x-5+2x+10+4x-9={540}^0$
$\Rightarrow 13x={520}^0$
$\Rightarrow x={40}^0$