Find the area of the shaded region in terms of pi.

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Discussion Overview

The discussion revolves around calculating the area of a shaded region in terms of pi, specifically focusing on the areas of a full circle and sectors. The context includes mathematical reasoning and problem-solving related to geometry.

Discussion Character

  • Mathematical reasoning

Main Points Raised

  • One participant states that the area of the full circle is πr² and calculates the area of a sector as (120/360)(πr²), resulting in 12π.
  • Another participant agrees with the calculation for the area of the full circle and prompts the completion of the second calculation.
  • A participant assumes the radius is 12 m and calculates the area for the second sector as (270/360)π(12²), arriving at 108π.
  • A later reply confirms the area calculation using the formula A=(1/2)r²θ, substituting the radius and angle to also arrive at 108π m².

Areas of Agreement / Disagreement

Participants generally agree on the calculations for the areas of the sectors, but there is no explicit consensus on the overall area of the shaded region or its implications.

Contextual Notes

Assumptions regarding the radius and the angles used in the calculations are present, but not all steps or definitions are fully resolved.

Etrujillo
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So far i have.

12) area of full circle is πr²
area of sector is (120/360)(πr²) or 12π

13) same
area is (270/360)(πr²)

Am i correct?

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#12 is correct ... finish #13
 
Im assuming 12m is the radius so \frac{270}{360}pi×12squared=108 pi
Am i correct?
 
$$A=\frac{1}{2}r^2\theta=\frac{1}{2}(12\text{ m})^2\frac{3\pi}{2}=108\pi\text{ m}^2\quad\checkmark$$
 

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