Answer:
38.9 square inches.
Step-by-step explanation:
We are asked to find the difference in area covered by a single 3 inch windshield wiper operating with a central angle of 138 degrees compared to a pair of 5 inch wipers operating together each having a central angle of 114 degrees.
We will use area of sector formula to solve our given problem as:
[tex]\text{Area of sector}=\frac{\theta}{360}\times \pi r^2[/tex], where, r represents radius and theta represents central angle.
Let us find area of sector with central angle 140 degree and radius 3 inch.
[tex]\text{Area of sector}=\frac{138}{360}\times \pi (3)^2[/tex]
[tex]\text{Area of sector}=\frac{138}{360}\times 9\pi[/tex]
[tex]\text{Area of sector}=10.83849[/tex]
Now, we will find area of sector with central angle 114 degree and radius 5 inch and multiply by 2 as:
[tex]\text{Area of sector}=2(\frac{114}{360}\times \pi (5)^2)[/tex]
[tex]\text{Area of sector}=2(\frac{114}{360}\times 25\pi)[/tex]
[tex]\text{Area of sector}=\frac{114}{360}\times 50\pi[/tex]
[tex]\text{Area of sector}=49.74188[/tex]
Let us find difference of area as shown below:
[tex]\text{Difference of areas}=49.74188-10.83849[/tex]
[tex]\text{Difference of areas}=38.90339[/tex]
[tex]\text{Difference of areas}\approx 38.9[/tex]
Therefore, the difference in area covered is approximately 38.9 square inches.