- A
- B
- C
- D
Step-by-Step Solution
LSA = . Trap 10,: one side face only . Trap 20,: two side faces only. Trap 43,: that is the TSA — it adds the two end squares (3,), which are not side faces.
Answer: B)
A pillar is a cuboid with a square base of side 40 cm and a height of 250 cm. Find the area of its four side faces.
Class 8MensurationMensuration
Key idea: Surface area of a cuboid
A cuboid has 3 pairs of identical opposite faces. Their total area:
- 2 faces of (top + bottom)
- 2 faces of (front + back)
- 2 faces of (left + right)
**TSA of cuboid = .**
**LSA of cuboid = ** — only the four side walls, used for room painting (not floor/ceiling).
Special case (cube, ): TSA = , LSA = .
- 2 faces of (top + bottom)
- 2 faces of (front + back)
- 2 faces of (left + right)
**TSA of cuboid = .**
**LSA of cuboid = ** — only the four side walls, used for room painting (not floor/ceiling).
Special case (cube, ): TSA = , LSA = .
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