The windshield wiper at the back of a hatchback has an 18 inch blade mounted on a 10 inch arm. If the wiper turns through an angle of 124 degrees, what area is swept clean?
2006-11-16 13:51:03 · 4 answers · asked by dance_inside 3 in Education & Reference ➔ Homework Help
I have no idea, but i think you may have to subtract them
2006-11-16 14:01:55 · answer #1 · answered by shadow_the_echinda 2 · 0⤊ 0⤋
Todd is on the right track.
I am assuming that mounting point of the blade is at its centre. So the radius of your circle is 10 +18/2 = 19 inches.
The total area of a circle with this radius is pi r^2
Since the blade only passes through 124 degrees, only a fraction of the circle is swept clean. (124 deg of a possible 360 degrees)
My answer:
Total Circle: pi r^2 = 361 pi inches sq.
x 124/360 = 124 pi inche sq.
= approx. 390 inches sq.
2006-11-16 22:55:40 · answer #2 · answered by Mr H 1 · 0⤊ 0⤋
If it had gone 360 degrees it would be the area of a circle. pi Rsquared. So when it traveled 90 degrees figure the area of a circle and divide it 1/4. So what is left is 34degrees cross multiply 90/34=254.34/x. I'm not gonna do it for you hopefully gave you the idea
2006-11-16 22:15:38 · answer #3 · answered by Todd C 4 · 0⤊ 0⤋
you would have to draw it out and use a protractor. dont actually measure like 18 inches but use a scale or ratio to help draw a small picture.
2006-11-16 22:01:19 · answer #4 · answered by megan'sthename 2 · 0⤊ 0⤋