Difficulty: Medium
Correct Answer: Area 120 sq cm, Perimeter 52 cm
Explanation:
Introduction / Context:
This problem checks two core rhombus facts: (1) Area can be found directly from diagonals using Area = (d1*d2)/2, and (2) diagonals bisect each other at right angles, allowing side length to be found by the Pythagoras theorem using half-diagonals. Once the side is known, perimeter is 4 times the side. The main goal is to produce the correct ordered pair: (area, perimeter).
Given Data / Assumptions:
Concept / Approach:
Compute area using diagonals formula. Compute side using right triangle formed by half diagonals. Then perimeter = 4*s. Keep units consistent (sq cm for area, cm for perimeter).
Step-by-Step Solution:
Area = (d1*d2)/2 = (24*10)/2 = 240/2 = 120 sq cmHalf diagonals are 12 cm and 5 cmSide s = sqrt(12^2 + 5^2) = sqrt(144 + 25) = sqrt(169) = 13 cmPerimeter = 4*s = 4*13 = 52 cm
Verification / Alternative check:
Since 12-5-13 is an exact Pythagorean triple, side = 13 is exact. Also area calculation is direct and exact. Therefore the ordered result (120, 52) is consistent and does not require rounding.
Why Other Options Are Wrong:
Area 240 doubles the correct area because the division by 2 was missed. Perimeter 48 or 50 uses an incorrect side length due to not halving diagonals or incorrect square root. Area 110 or 130 indicates arithmetic mistakes in 24*10/2.
Common Pitfalls:
Forgetting Area = (d1*d2)/2. Not halving diagonals before Pythagoras. Mixing up units (writing cm for area). Giving only one value when the question asks for both in order.
Final Answer:
Area 120 sq cm, Perimeter 52 cm
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