12 multiple-choice questions, progressively harder.
Two pieces have disjoint interiors and meet only along a face. Their volumes are 45 and 28 cubic centimeters. What is the joined volume?
Solution
Correct answer: B
No region with positive volume is shared, so add the volumes.
The joined volume is 73 cubic centimeters.
A solid of volume 144 cubic centimeters has a cavity of volume 35 cubic centimeters removed. How much material remains?
Correct answer: D
Subtract the empty cavity from the original solid.
There are 109 cubic centimeters of material.
Two solids with disjoint interiors have total surface areas 90 and 78 square centimeters. They meet over one matching face of area 12 square centimeters, with no other contact. Find the exterior area.
Correct answer: A
Both copies of the joining face become internal.
The exterior area is 144 square centimeters.
A right circular pipe has outer radius 3 cm, inner radius 2 cm, and length 5 cm. Find its material volume.
Correct answer: C
Subtract the full coaxial bore.
The material volume is 25π25\pi25π cubic centimeters.
One end of an open pipe is an annulus with outer radius 6 cm and inner radius 4 cm. What is the area of that one end?
The annulus is the outer disk with the inner disk removed.
Its area is 20π20\pi20π square centimeters.
A right circular cylinder of length 9 cm has a hemisphere of radius 4 cm attached at each end. What is the full tip-to-tip length?
Each hemispherical end extends one radius along the axis.
The full length is 17 cm.
A cylinder of radius 2 cm and length 3 cm has one solid hemisphere of the same radius attached to an end. What is the total volume?
Add one cylinder and one hemisphere.
The volume is 52π3\frac{52\pi}{3}352π cubic centimeters.
A radius-3 cm hemisphere is attached flush to one end of a right cylinder of radius 3 cm and height 4 cm. The other cylinder end is flat and exposed. What is the exterior area, including that flat end?
Count the cylinder side, hemisphere curve, and one flat base.
The exterior area is 51π51\pi51π square centimeters. The joined disks are internal.
A rectangular box has perpendicular edges 4 cm, 4 cm, and 7 cm. Find a space diagonal.
Use two right triangles, or combine their squared relations.
The squared diagonal is 81 square centimeters, so its positive length is 9 cm.
A thick pipe is open at both ends and hangs freely. A coating must cover every material surface, including inside the bore. Which list is complete?
The bore is empty, so there are no disks across it. Its wall is exposed. Each end still has an annular ring of material. These, together with the outside wall, are all the requested surfaces.
Two solid parts meet only along their boundaries, with no gaps or overlapping interiors. Why can their volumes be added?
Volume measures occupied three-dimensional regions. A shared boundary has no thickness, so it adds no duplicate volume. Its area can be positive, which is why surface accounting is a separate question.
A block is 5 cm by 6 cm by 7 cm. A radius-1 cm cylindrical hole passes perpendicularly through the 7 cm thickness, strictly inside the 5 cm by 6 cm faces. What is the remaining volume?
The bore length is 7 cm.
The remaining volume is (210−7π)(210-7\pi)(210−7π) cubic centimeters.
Reset this practice set?
This clears every answer you have given and starts the set again from question 1.