Q. If the radius of a circle is doubled, what happens to its area? (2020)
A.It remains the same
B.It doubles
C.It triples
D.It quadruples
Solution
The area of a circle is given by A = πr². If the radius is doubled (r becomes 2r), the new area is A' = π(2r)² = 4πr², which is four times the original area.
Q. In a right triangle, if one angle is 30 degrees, what is the ratio of the lengths of the sides opposite to the 30 degrees and 60 degrees angles? (2019)
A.1:√3
B.1:2
C.√3:1
D.2:1
Solution
In a 30-60-90 triangle, the sides opposite the 30 degrees and 60 degrees angles are in the ratio 1:√3.
Q. What is the length of the diagonal of a rectangle with length 6 cm and width 8 cm? (2022)
A.10 cm
B.12 cm
C.14 cm
D.16 cm
Solution
The length of the diagonal d of a rectangle can be found using the Pythagorean theorem: d = √(length² + width²) = √(6² + 8²) = √(36 + 64) = √100 = 10 cm.