Question

In figure, line $l||m$, $\angle 1={120}^o$ and $\angle 2={100}^o$, find out $\angle 3$ and $\angle 4$.

Answer 1

As per the given figure,

$\angle 2=\angle y={100}^o$ [corresponding angles ]

$\angle 3={180}^o-\angle y=180-{100}^o={80}^o$ [ Angles in a straight line ]

$\angle x={180}^o-\angle 1=180-{120}^o={60}^o$ [ Angles in a straight line ]

We know that sum of angles in a triangles is ${180}^o$

$\angle x+\angle 3+\angle 4={180}^o$

$60+80+\angle 4={180}^o$

$\angle 4=180-{140}^o$

$\therefore \angle 3={80}^o$ and

$\angle 4={40}^o$