- A₹1080
- B₹270
- C₹4050
- D₹8100
Step-by-Step Solution
Area = . Cost = 225 × ₹18 = ₹4050. Using the perimeter (60 m) instead of the area gives the trap ₹1080; using just the side length gives ₹270.
Answer: C) ₹4050
A square courtyard has side 15 m. It is plastered over its whole surface at ₹18 per square metre. Find the total cost of plastering.
Class 7Perimeter and AreaPerimeter and Area
Key idea: Parallelogram area
**Area of a parallelogram = base × height.**
Same idea as a rectangle, but the height is the perpendicular distance between the two parallel sides — NOT the slant length of the side. Pick any side as the base, drop a perpendicular to the opposite parallel side, measure that — that's the height.
Example: parallelogram with base 8 cm and perpendicular height 5 cm. Area = . The slant side could be longer; doesn't matter for area.
Perimeter of a parallelogram = 2 × (one side + adjacent side).
Same idea as a rectangle, but the height is the perpendicular distance between the two parallel sides — NOT the slant length of the side. Pick any side as the base, drop a perpendicular to the opposite parallel side, measure that — that's the height.
Example: parallelogram with base 8 cm and perpendicular height 5 cm. Area = . The slant side could be longer; doesn't matter for area.
Perimeter of a parallelogram = 2 × (one side + adjacent side).
Master this chapter in 30 minutes a day.
Don't just memorise the answer — build a daily practice habit.
Practice 5 Similar Questions Free →All Perimeter and Area practice questions
More Class 7 Perimeter and Area practice
A parallelogram-shaped kitchen garden has adjacent sides 24 m and 16 m, and the height…A circular cricket ground has a diameter of 154 m. A fielder at the exact centre throws…The side of a square is increased to three times its original length. What happens to…The perimeter of a rectangular kitchen slab is 26 m and its breadth is 5 m. Find its…A contractor is quoting for four jobs. For which ONE of them must he work out the AREA…