Question

In figure, if lines l and m are parallel lines, then x=

• A. ${70}^0$
• B. ${30}^0$
• C. ${40}^0$
• D. ${100}^0$

Answer 1

The correct option is C ${40}^0$

Given: l||m

$\angle 1={70}^0$ (corresponding angles)

In $\Delta DEF$,
$\angle 1=x+{30}^0$
(Exterior angle is equal to the sum of opposite interior angles)

$\Rightarrow {70}^0=x+{30}^0$
$\Rightarrow x={70}^0-{30}^0$
$\Rightarrow x={40}^0$

Hence, option (c) is correct.