Answer:
28.740,
Step-by-step explanation:
First subtract 2 revolutions from the - 840 :- (- (840-720) = -120
This gives sin -120 which is in the 3rd quadrant of the unit circle
sin -120 = - sin 60 = - sqrt3/2
Length - l
Width - w
Given,
Perimeter = 60
2(l +w) = 60
l + w = 30
l = 30 - w
Given,
l = 3w
30 - w = 3w
4w = 30
--- w = 7.5
--- l = 3w = 3 * 7.5 = 29.5
Hence, the length of the rectangle is 29.5 and the width is 7.5
