The length and breadth of a rectangle are in the ratio 5:4. Find its perimeter if its area is 180 cm²
Correct answer: A. 54 cm
- A. 54 cm
- B. 27 cm
- C. 12 cm
- D. 15 cm
Explanation
Let the length and breadth be 5k cm and 4k cm. Since the area is 180 cm², 5k × 4k = 20k² = 180, so k² = 9 and k = 3 cm; the sides are 15 cm and 12 cm. The perimeter is 2(15 cm + 12 cm) = 54 cm. The likely trap is option b, 27 cm, which is the sum of the two side lengths rather than the full perimeter.
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Area measures the surface enclosed by two-dimensional figures, while volume measures the space occupied by three-dimensional solids. Problems use formulas for rectangles, triangles, circles, prisms, cylinders, cones, spheres, and composite figures, including unit conversion and the distinction between surface area, lateral area, and volume.
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