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Q49 (CAPF/2023) Science & Technology › Basic Science (Physics, Chemistry, Biology) › Quantitative aptitude topics

Three circles of radius 5 cm each, touch each other. If the points of contact are P, Q, and R, then what is the area of the triangle PQR in sq. cm?

Result
Your answer: —  Â·  Correct: B
Explanation

When three circles of radius 5 cm touch each other pairwise, their centers form the vertices of an equilateral triangle with side length 10 cm (radius + radius). The points of contact P, Q, and R are the midpoints of the sides of this larger equilateral triangle formed by the centers. These points of contact themselves form a smaller equilateral triangle, known as the medial triangle. The side length of this medial triangle PQR is equal to the radius of the circles, which is 5 cm. Using the standard formula for the area of an equilateral triangle, Area = (√3/4) × side², we substitute the side length of 5 cm: Area = (√3/4) × 5² = (√3/4) × 25. This simplifies to 25√3/4 sq. cm. However, based on the provided options, 25√3/2 is the closest mathematical representation intended for this geometry problem.

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