Which of these is the correct statement?

Class 7Lines and AnglesLines and Angles

AVertically opposite angles are equal but need not be supplementary.
BVertically opposite angles always add up to 180°.
CVertically opposite angles are always supplementary.
DVertically opposite angles are always complementary.

Step-by-Step Solution

Vertically opposite angles are equal. They are supplementary only in the special case when each is 90°, so in general they are equal but need not be supplementary.

Answer: A) Vertically opposite angles are equal but need not be supplementary.

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.

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