The radius of a semicircle is 6.3 cm. Find its perimeter. A. 35.4 cm B. 32.4 cm C. 32 cm D. 30 cm Explanation: Perimeter = πr + 2r.
A cylinder has a radius of 7 cm and a height of 3 cm. Find the total surface area. A. 308 cm² B. 220 cm² C. 440 cm² D. 132 cm² Explanation: TSA = 2πr(r+h).
The radius of a cylinder is r, and the height is 3r. Find the curved surface area. A. 18πr² B. 3πr² C. 12πr² D. 6πr² Explanation: CSA = 2πr × 3r = 6πr².
A circular wheel of radius 1.75 m makes how many revolutions in 11 km? A. 1000 B. 2000 C. 3000 D. 4000 Explanation: Revolutions = distance/circumference.
The radius of a cylinder equals that of a sphere. Compare their volumes. A. 4/3 times B. 2/3 times C. Equal D. Equal to diameter Explanation: Sphere volume = 4/3 πr³ vs cylinder πr²h.
The radius of a circle is increased by 1%. By what percent does its area increase? A. 1.01% B. 5.01% C. 3.01% D. 2.01% Explanation: Area ∝ r² → increase ≈ 2.01%.
A lotion contains 50% alcohol. How much water must be added to reduce the alcohol content to 25% in 9 ml? A. 3 ml B. 4 ml C. 5 ml D. 6 ml Explanation: Using the dilution Equation yields 6 mL of water.
The product of two numbers is 4107, and their HCF is 37. Find their LCM. A. 101 B. 107 C. 111 D. 185 Explanation: LCM = 4107/37 = 111.
The product of two numbers is 2028, and their HCF is 13. How many such pairs exist? A. 1 B. 2 C. 3 D. 4 Explanation: Factorization yields two valid coprime pairs.
The product of two numbers is 2025, and their HCF is 15. Find their LCM. A. 2040 B. 2010 C. 135 D. 150 Explanation: LCM = product ÷ HCF = 2025/15 = 135.