Question

$\angle x + \angle y$ equals:

• A. ∠a - ∠b
• B. 2(∠a + ∠b)
• C. 2(∠a - ∠b)
• D. ∠a + ∠b

Answer 1

The correct option is D $(\angle a+\angle b)$

Since, the two horizontal lines are parallel,
So, from the rule of alternative angles, we get
$\angle x=\angle a$ ..........(i) and
$\angle y=\angle b$ ..........(ii)
Adding equation(1) and (2), we get
$\angle x+\angle y=\angle a+\angle b$
Hence, the correct option is D.