Difficulty: Easy
Correct Answer: 120 m^2
Explanation:
Introduction / Context:
This question tests how to use the Pythagoras theorem in a rectangle. In any rectangle, the diagonal, length, and breadth form a right-angled triangle. If you know one side and the diagonal, you can find the other side and then compute the area as length * breadth.
Given Data / Assumptions:
Concept / Approach:
Use Pythagoras theorem on the right triangle formed by the sides and diagonal: diagonal^2 = side^2 + other_side^2. Then compute area = side * other_side.
Step-by-Step Solution:
17^2 = 15^2 + x^2
289 = 225 + x^2
x^2 = 289 - 225 = 64
x = 8 m
Area = 15 * 8 = 120 m^2
Verification / Alternative check:
If the sides are 15 m and 8 m, the diagonal should be sqrt(15^2 + 8^2) = sqrt(225 + 64) = sqrt(289) = 17 m, which matches the given diagonal.
Why Other Options Are Wrong:
110 m^2: would require the other side to be 110/15 = 7.33 m, not consistent with the diagonal 17 m.
130 m^2: would require the other side to be 8.67 m, changing the diagonal.
140 m^2: would require the other side to be 9.33 m, changing the diagonal.
150 m^2: would require the other side to be 10 m; then diagonal becomes sqrt(15^2 + 10^2), not 17.
Common Pitfalls:
Forgetting that the diagonal with the sides forms a right triangle.
Squaring incorrectly (mixing up 17^2 and 15^2).
Finding the missing side but forgetting area needs multiplication of the two sides.
Final Answer:
Area of the field = 120 m^2
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