**Class Nine Mathematics Chap 10 extra Ques-answers**

**Chapter 10 : Circles**

#### Additional Questions-answers

**Very Short Answer Type Questions: [1 Mark] **

**1. **Which
is the longest chord of the circle?

**Sol. **Diameter
is the longest chord of the circle.

**2. **What is another name of the perimeter of a circle?

**Sol. The perimeter** of a circle is also known as the circumference of the circle.

**3. **If chords of a circle (or of congruent
circles) are equal then angle subtend at the centre by them will be equal? Is,
it true or false?

**Sol. **True

**4. **If
two chords of a circle subtend equal angles at the centre, what will be the
relationship between them?

**Sol. **Both the chords will be
equal.

**5. **What
is the minimum number of points required to determine a unique circle?

**Sol. **Minimum 3 points are
required to determine a unique circle.

**6. **How
many circles can be drawn from three non-collinear points?

**Sol. **One
and only one circle can be drawn from three non-collinear points.

**7. **What is the relationship between the chord of a circle and perpendicular to it from the centre?

**Sol. A perpendicular** line from the centre bisects the chord.

**8. **Two
chords AB and CD of a circle are each at a distance 4 cm from the centre. Then
Prove that AB = CD.

**Sol. **We know that the chords
which are equidistant from the centre of the circle are equal in length.

AB = CD

- In the given figure, O is the centre of the circle. If OA = 5 cm and OC = 3 cm, then find the length of AB.

Sol.

AB = 2 × AC = 2 × 4 cm = 8 cm.