Question

Line l₁ || l₂, ∠ABC = 90°. x = ______.

Options

• 50°

• 20°

• 70°

• 40°

Answer 1

Line l₁ || l₂, ∠ABC = 90°. x = 70°.

Explanation:

l₁ || l₂ so the 130° angle shown where BC meets l₁ corresponds to the angle between BC and l₂ also 130°. 

At C the angle between AC and l₂ is 110°.

So, the angle between BC and AC

= 130° – 110°

= 20°

Because AB ⟂ BC   ...(∠ABC = 90°)

The angle x = ∠BAC

= 90° – 20°

= 70°