Math Problem Statement

solve

एक घड़ी की मिनट की सुई r सेमी लंबी है। एक मिनट में मिनट की सुई द्वारा बनाए गए त्रिज्याखंड का क्षेत्रफल होगा।

Solution

The problem provided in the image is related to the area of a sector of a circle, where the minute hand of a clock sweeps through a specific angle in one minute.

Problem Analysis:

  1. The minute hand of the clock completes one full revolution (360°) in 60 minutes.
  2. Therefore, in one minute, the angle swept by the minute hand is: θ=36060=6\theta = \frac{360^\circ}{60} = 6^\circ
  3. The area of a sector of a circle is given by the formula: Sector Area=θ360πr2\text{Sector Area} = \frac{\theta}{360^\circ} \cdot \pi r^2 where rr is the length of the radius (minute hand), and θ\theta is the angle of the sector.

Substituting the values:

  • θ=6\theta = 6^\circ,
  • r2r^2 is the square of the radius,
  • The formula becomes: Sector Area=6360πr2=πr260\text{Sector Area} = \frac{6}{360} \cdot \pi r^2 = \frac{\pi r^2}{60}

Final Answer:

The area of the sector formed by the minute hand in one minute is: πr260\boxed{\frac{\pi r^2}{60}}

This matches Option (A).


Would you like further clarification on the formula or the steps? Here are five related questions to explore:

  1. How is the formula for the area of a sector derived?
  2. What would be the area swept in 15 minutes instead of 1 minute?
  3. How is the angle swept by the hour hand calculated, and how would the formula differ for it?
  4. What is the area swept in a full revolution of the clock's minute hand?
  5. Can you calculate the perimeter of the sector in this problem, including the arc length?

Tip: Always remember, for sector problems, knowing the angle is key to determining the fraction of the circle being considered.

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Math Problem Analysis

Mathematical Concepts

Geometry
Circle
Area of a Sector

Formulas

Area of a sector = (θ/360) × π × r²

Theorems

Sector Area Theorem

Suitable Grade Level

Grades 8-10