Practice30Create account

A ladder leans against a vertical wall that meets the level ground at a right angle. The ladder makes an angle of 63° with the ground. What angle does the ladder make with the wall?

Class 7Lines and AnglesLines and Angles
  • A27°
  • B117°
  • C63°
  • D37°

Step-by-Step Solution

The wall, the ground and the ladder make a right-angled corner, so the angle at the ground and the angle at the wall are complementary — they sum to 90°. Angle with the wall = 90 − 63 = 27°. Trap: 117° is 180 − 63, the SUPPLEMENT; it applies to angles on a straight line, not to the two acute angles inside a right-angled corner.
Answer: A) 27°

Key idea: Vertically opposite angles

When two straight lines cross, four angles form at the intersection. The two angles directly **across** the vertex (sharing only the vertex, not a side) are called **vertically opposite** — and they are always equal.

If one angle is 70°, then:
- Its vertical opposite is also 70°.
- The other two angles are each 110° (linear pair with 70°).

Why? Each pair forms a linear pair with a common neighbour, both summing to 180° — so the opposites end up equal.

Master this chapter in 30 minutes a day.

Don't just memorise the answer — build a daily practice habit.

Practice 5 Similar Questions Free →

All Lines and Angles practice questions

More Class 7 Lines and Angles practice

A see-saw plank rests on a pivot. On one side the plank makes an angle of 24° with the…Three straight lines all pass through a single point O, so six angles are formed around…Two parallel lines are cut by a transversal. A pair of angles lies OUTSIDE the parallel…Two angles lie BETWEEN two parallel lines and on the SAME side of the transversal that…An angle is three times its own supplement. Find the angle.