Precalc Trig Arc Length Question

In summary, The question is asking for the total perimeter of the area swept out by a windshield wiper, given the formula a=θr. The attempt at a solution provided [(5pi/6)*20] + 16(2) + [(5pi/6)*4], but the word "total" was missed, leading to an incorrect solution. The correct solution is [(5pi/6)*20] + 16(2) + [(5pi/6)*4] + 2(5pi/6).
  • #1
A123
4
0

Homework Statement


http://education.Alberta.ca/media/9451970/07_math30-1_released_2014-15.pdf
question #7

Homework Equations


a=theta*r

The Attempt at a Solution


I did a=(5pi/6)*20 but the answer is not A
 
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  • #2
A123 said:

Homework Statement


http://education.Alberta.ca/media/9451970/07_math30-1_released_2014-15.pdf
question #7

Homework Equations


a=theta*r

The Attempt at a Solution


I did a=(5pi/6)*20 but the answer is not A
I think 'total perimeter' here means you go entirely around the area which is swept out by the wiper.
 
  • #3
SteamKing said:
I think 'total perimeter' here means you go entirely around the area which is swept out by the wiper.
I agree with SteamKing's appraisal.
 
  • #4
SteamKing said:
I think 'total perimeter' here means you go entirely around the area which is swept out by the wiper.

Yeah I just went back to it and I missed that word completely lol.
Its [(5pi/6)*20] + 16(2) + [(5pi/6)*4]
I was too focused on what's inside
 

Related to Precalc Trig Arc Length Question

What is the formula for finding arc length in precalculus trigonometry?

The formula for finding arc length is s = rθ, where s is the arc length, r is the radius of the circle, and θ is the central angle in radians.

How do I convert degrees to radians?

To convert degrees to radians, multiply the degree measure by π/180. For example, to convert 45 degrees to radians, we would do 45 * π/180 = π/4.

What is the difference between arc length and arc measure?

Arc length is the actual distance along the circumference of a circle, while arc measure is the central angle in radians that corresponds to that arc length.

Can I use the formula for arc length in any shape?

No, the formula s = rθ only applies to circles. For other shapes, you would need to use different formulas to find the arc length.

How do I find the arc length if the central angle is given in degrees?

If the central angle is given in degrees, you would need to convert it to radians first before using the formula s = rθ. You can do this by multiplying the degree measure by π/180.

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