Volume of combined solids
Grade 10 Math Worksheet

Circle the best answer.
Sketch, not to scale. A cone is 12 cm tall with radius 6 cm. Bo cuts off the top 4 cm parallel to the base and says the top cone is 1/27 of the whole. What licenses 1/27?
- The top cone's base area is 1/9 of the whole, so its volume is also 1/9 of it
- It is similar with scale 1/3, so volume scales by (1/3)³
- The top looks small on the page, about one tenth of the whole cone by eye
- The top cone is similar with scale 1/3, so its volume is 1/3 of the whole cone
A cone and a square pyramid both have base area 30 cm² and height 12 cm. Esme wants to show equal volumes without using volume formulas. Which argument works?
A cone and a square pyramid, each with base area 30 cm² and height 12 cm. Sketch, not to scale. A cone and a square pyramid, each with base area 30 cm² and height 12 cm. Sketch, not to scale. A cone and a square pyramid, each with base area 30 cm² and height 12 cm Not to scale. - Both have base area 30, and the base area alone decides the volume of a solid
- Both come to a point at the top, so their volumes must be equal by that shape
- Equal slice areas at every height, so Cavalieri gives equal volumes
- Both have the same slant height, so their volumes are equal because slant decides
A rock is lowered into a cylinder 10 cm across. The water level rises 2 cm. Sketch, not to scale. A rock sinks into a cylinder 10 cm across and the water rises 2 cm. Jun says the rock's volume is the base area times the rise. What licenses that?
A rock is lowered into a cylinder 10 cm across. The water level rises 2 cm. Sketch, not to scale. A rock is lowered into a cylinder 10 cm across. The water level rises 2 cm. Sketch, not to scale. 10 cm across 2 cm - The rock's volume equals one third of the base area times the rise, as for a cone
- It pushes aside equal water: the tank's base times the rise
- The rock's volume equals the base area times the new depth of the water
- The rock's volume equals the area of a circle 10 cm in radius times the rise
Kira says a bucket with radii 6 and 3 cm and height 8 cm has the same volume as a can of average radius 4.5 cm and height 8 cm. Which reply is right?
A bucket (a cone with its tip cut off) with radii 6 cm and 3 cm and height 8 cm, and a can with radius 4.5 cm and height 8 cm. Sketch, not to scale. A bucket (a cone with its tip cut off) with radii 6 cm and 3 cm and height 8 cm, and a can with radius 4.5 cm and height 8 cm. Sketch, not to scale. Sketch, not to scale bucket 3 cm 6 cm 8 cm can 4.5 cm 8 cm - Yes: both have straight sides and the same height, so they hold the same
- Yes: the halfway radius gives the halfway volume of the two cones
- No: the bucket is 168π and the can is 162π, since volume follows r²
- No: the can is 192π, the volume of the big cone alone, and the bucket is less
Milo says two solids with equal height and equal base area always have equal volume. Which reply is right?
A cylinder and a cone with the same base and the same height. Sketch, not to scale. A cylinder and a cone with the same base and the same height. Sketch, not to scale. A cylinder and a cone with the same base and the same height Not to scale. - Yes: each is one third of base times height, so they must agree anyway
- No: they match only if their slant heights match as well as the base
- No: Cavalieri needs equal slices at every height; cylinder and cone differ 3 to 1
- Yes: the same base and the same height make the same volume for every solid
Noah says a ball of radius 3 cm is exactly two thirds of the snug cylinder around it (radius 3, height 6). Which reply is right?
A ball of radius 3 cm fits snugly inside a cylinder of radius 3 cm and height 6 cm. Sketch, not to scale. A ball of radius 3 cm fits snugly inside a cylinder of radius 3 cm and height 6 cm. Sketch, not to scale. 3 cm ball 6 cm 3 cm cylinder Not to scale. - No: the ball is π/4 of the cylinder, like a circle in a square, so under 80%
- Yes: the ball is half the cylinder, which looks right
- Yes: the ball is 36π, the cylinder is 54π, and 36π/54π = 2/3
- No: the ball is one third of the cylinder, like a cone in its can, so less
Pia finds a pyramid's volume (base 6 cm square, slant height 5 cm): Line 1: height = 5 − 3 = 2. Line 2: volume = (1/3)(36)(2) = 24. Which line is wrong?
A square pyramid with base 6 cm on a side and slant height 5 cm, measured from the base edge's midpoint to the apex. Sketch, not to scale. A square pyramid with base 6 cm on a side and slant height 5 cm, measured from the base edge's midpoint to the apex. Sketch, not to scale. 5 cm 6 cm slant height 5 cm, measured from the base edge's midpoint to the apex Not to scale. - Line 1: the height is √(5² − 3²) = 4 by Pythagoras, not 5 − 3
- Neither line is wrong; just the units are missing from the final answer
- Line 2: the pyramid formula has no one third, so the volume is 72
- Line 2: the base area should be 6 × 3 = 18, using half of one side
Ren finds a silo's volume (cylinder radius 3 m, height 10 m, half-ball top): Line 1: cylinder 90π. Line 2: half-ball (4/3)π·27 = 36π. Line 3: total 126π. Which line is wrong?
A silo: a cylinder 6 m across and 10 m tall with a half-ball of the same width on top. Sketch, not to scale. A silo: a cylinder 6 m across and 10 m tall with a half-ball of the same width on top. Sketch, not to scale. A silo 10 m 6 m 6 m a cylinder 6 m across and 10 m tall with a half-ball of the same width on top Not to scale. - Line 2: a half-ball is half a ball, (2/3)π·27 = 18π
- Line 3: add another 36π for a second half-ball at the bottom of the silo
- No line is wrong; just the units are missing from the total
- Line 1: the cylinder should use radius 6 because the silo is 6 m across
Tala finds a rock's volume (cylinder 10 cm across, water from 10 cm to 12 cm): Line 1: rise = 2 cm. Line 2: volume = π·5²·12. Which line is wrong?
A rock is lowered into a cylinder 10 cm across. The water level rises from 10 cm to 12 cm. Sketch, not to scale. A rock is lowered into a cylinder 10 cm across. The water level rises from 10 cm to 12 cm. Sketch, not to scale. Sketch, not to scale 12 cm 10 cm rock 10 cm across - Line 2: the volume uses the rise, 2 cm, not the depth, 12 cm
- Line 2: use π·5·2, with the radius not squared, since the rock is solid
- Line 2: the radius should be 10 cm, because the cylinder is 10 cm across
- Line 1: the rise should be 12 cm, the depth of the water after the rock
Zee finds a cone's height (radius 5 cm, volume 100π cm³): Line 1: (1/3)π·25·h = 100π. Line 2: 25h = 100. Line 3: h = 4. Which line is wrong?
A cone with base radius 5 cm and volume 100π cm³. Sketch, not to scale. A cone with base radius 5 cm and volume 100π cm³. Sketch, not to scale. A cone with base radius 5 cm and volume 100pi cm³ 5 cm Not to scale. - Line 1: the cone formula has no one third, so the equation is wrong from the start
- Line 2: times 3 gives 25h = 300, so h = 300 ÷ 25 = 12
- Line 1: the radius should be 10 cm, as the cone base is wide
- Line 3: divide 25h = 100 by 25π, because the π was not removed