Online Test — Circles
10 Questions • 15 min • Chapter MCQ
15:00
Question 1 of 10
What is the mathematical relationship between the radius (\(r\)) and diameter (\(d\)) of a circle?
\(r = 2d\)
\(d = 2r\)
\(d = r^2\)
\(r = d^2\)
Explanation: The diameter is twice the length of the radius.
Question 2 of 10
What is the term for a line segment connecting two points on a circle that does NOT pass through the center?
Radius
Tangent
Chord
Sector
Explanation: A chord connects two edge points; it only becomes a diameter if it crosses the center.
Question 3 of 10
If the radius of a circular coin is \(21\text{ mm}\), what is its circumference? (Use \(\pi = \frac{22}{7}\))
\(66\text{ mm}\)
\(132\text{ mm}\)
\(1386\text{ mm}\)
\(441\text{ mm}\)
Explanation: \(C = 2 \times \frac{22}{7} \times 21 = 2 \times 22 \times 3 = 132\text{ mm}\).
Question 4 of 10
Find the area of a circle whose radius is \(7\text{ cm}\). (Use \(\pi = \frac{22}{7}\))
\(44\text{ cm}^2\)
\(49\text{ cm}^2\)
\(154\text{ cm}^2\)
\(308\text{ cm}^2\)
Explanation: \(\text{Area} = \frac{22}{7} \times 7 \times 7 = 154\text{ cm}^2\).
Question 5 of 10
The circumference of a circular table is \(88\text{ cm}\). Find its radius. (Use \(\pi = \frac{22}{7}\))
\(7\text{ cm}\)
\(14\text{ cm}\)
\(28\text{ cm}\)
\(44\text{ cm}\)
Explanation: \(2 \times \frac{22}{7} \times r = 88 \implies \frac{44}{7}r = 88 \implies r = 14\text{ cm}\).
Question 6 of 10
If you double the radius of a circle, what happens to its diameter?
It stays the same
It is halved
It is doubled
It is quadrupled
Explanation: Since \(d=2r\), multiplying \(r\) by \(2\) multiplies \(d\) by \(2\).
Question 7 of 10
What shape is a region bounded by an arc and two radii?
Segment
Chord
Sector
Diameter
Explanation: A sector is a pie-shaped region enclosed by two radii and an arc.
Question 8 of 10
Find the area of a circular mirror if its diameter is \(20\text{ cm}\). (Use \(\pi = 3.14\))
\(62.8\text{ cm}^2\)
\(125.6\text{ cm}^2\)
\(314\text{ cm}^2\)
\(1256\text{ cm}^2\)
Explanation: \(r = 10\text{ cm}\). \(\text{Area} = 3.14 \times 10 \times 10 = 314\text{ cm}^2\).
Question 9 of 10
A circular wheel has a diameter of \(10\text{ cm}\). How far does it roll in \(1\) complete turn? (Use \(\pi = 3.14\))
\(15.7\text{ cm}\)
\(31.4\text{ cm}\)
\(78.5\text{ cm}\)
\(314\text{ cm}\)
Explanation: Distance in \(1\) turn \(= C = \pi d = 3.14 \times 10 = 31.4\text{ cm}\).
Question 10 of 10
The area of a circle is \(616\text{ cm}^2\). Find its radius. (Use \(\pi = \frac{22}{7}\))
\(7\text{ cm}\)
\(14\text{ cm}\)
\(21\text{ cm}\)
\(28\text{ cm}\)
Explanation: \(\frac{22}{7}r^2 = 616 \implies r^2 = 616 \times \frac{7}{22} = 196 \implies r = 14\text{ cm}\).