Hi can I get help with these two questions.

1. Everytime the pedals go through 360 degree rotation, the tires roate three imes. if the tires are 24 nches in diameter, what is the minimum numbe of comlete rotions of the pedls needed forr the bicycle to travel at least 1 mile.

I got 561 rotations.

2. If the sine of an angle is 3/5 and the ange is not in Quadrant I,what is the value of the cosine of the angle.

Is it -4/5 or -.79863551

1 answer

1. each pedal moves the bike 3 pi* 2 ft = 18.85 feet. One mile is 5280 ft
5280 ft/18.89 ft/pedal = 280 rotations

I think you assumed the diameter was the radius.

2. If the sine is positive and the angle is not positve, you are in the second quadrant.
cosx = - sqrt (1 - sin^2x) = -4/5