Surface Areas and Volumes — Questions & Answers

Sample questions from Surface Areas and Volumes

1. Q1. The surface area of sphere r=7 cm using π=22/7 is: Verify the related solid calculation:

   • A.616 cm²✓
   • B.308 cm²
   • C.154 cm²
   • D.44 cm²
   Solution

   4πr²=4×22/7×49=616 cm².

2. Q2. The volume of a cone is:

   • A.1/3πr²h✓
   • B.πr²h
   • C.1/2πr²h
   • D.πrl
   Solution

   A cone has one-third the volume of a cylinder with same base and height.

3. Q3. A cylinder of radius 7 cm and height 10 cm is melted into cubes of side 1 cm. Number of cubes using π=22/7 is:

   • A.1540✓
   • B.440
   • C.770
   • D.3080
   Solution

   Cylinder volume=1540 cm³, so it makes 1540 unit cubes.

4. Q4. Which of these is measured in square units?

   • A.The volume of a cone
   • B.The capacity of a vessel
   • C.The slant height of a cone
   • D.The total surface area of a cylinder✓
   Solution

   D is correct: an area is measured in square units. A and B are volumes, measured in cubic units, and capacity is simply volume under another name. C is a length, measured in ordinary units.

5. Q5. The total surface area of a cube of side 5 cm is:

   • A.150 cm²✓
   • B.25 cm²
   • C.100 cm²
   • D.125 cm²
   Solution

   6a²=6×25=150 cm².

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