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How do you work out the area if given the circumference?
Assuming the shape concerned is a circle, Radius = Circumference/(2*pi)and thenArea = pi*(radius)2= pi*(circumference)2/(2*pi)2= (circumference)2/(4*pi)Assuming the shape concerned is a circle, Radius = Circumference/(2*pi)and thenArea = pi*(radius)2= pi*(circumference)2/(2*pi)2= (circumference)2/(4*pi)Assuming the shape concerned is a circle, Radius = Circumference/(2*pi)and thenArea = pi*(radius)2= pi*(circumference)2/(2*pi)2= (circumference)2/(4*pi)Assuming the shape concerned is a circle, Radius = Circumference/(2*pi)and thenArea = pi*(radius)2= pi*(circumference)2/(2*pi)2= (circumference)2/(4*pi)
If the circumference of a circle is 9.42 what is its area?
C = 2 pi R = 9.42 R = 9.42 / (2 pi) A = pi R2 = pi [ 9.42 / (2 pi) ]2 = (9.42)2 pi / 4 pi2 = (9.42)2 / (4 pi) = 7.0614 (rounded) ======================================== I just thought of something: C = 2 pi R A = pi R2 = 1/2 (2 pi R) x (R) = 1/2 (2 pi R) x (1/2pi) (2 pi R) = C/2 x C/(2 pi) = C2 / (4 pi)Let's see if this gives the same answer as above: C2 / (4 pi) = (9.42)2 / (4 pi) = 7.0614 Yay ! Next time, I'll remember that the area is (circumference2) divided by (4 pi).
What is the exact value using a sum or difference formula of the expression cos 11pi over 12?
11pi/12 = pi - pi/12 cos(11pi/12) = cos(pi - pi/12) cos(a-b) = cos(a)cos(b)+sin(a)sin(b) cos(pi -pi/12) = cos(pi)cos(pi/12) + sin(pi)sin(pi/12) sin(pi)=0 cos(pi)=-1 Therefore, cos(pi -pi/12) = -cos(pi/12) pi/12=pi/3 -pi/4 cos(pi/12) = cos(pi/3 - pi/4) = cos(pi/3)cos(pi/4)+sin(pi/3) sin(pi/4) cos(pi/3)=1/2 sin(pi/3)=sqrt(3)/2 cos(pi/4)= sqrt(2)/2 sin(pi/4) = sqrt(2)/2 cos(pi/3)cos(pi/4)+sin(pi/3) sin(pi/4) = (1/2)(sqrt(2)/2 ) + (sqrt(3)/2)( sqrt(2)/2) = sqrt(2)/4 + sqrt(6) /4 = [sqrt(2)+sqrt(6)] /4 Therefore, cos(pi/12) = (sqrt(2)+sqrt(6))/4 -cos(pi/12) = -(sqrt(2)+sqrt(6))/4 cos(11pi/12) = -(sqrt(2)+sqrt(6))/4
What is the sin of pi divided by 2?
Do you mean Sin(pi/2) = 1 or [Sin(pi)] /2 = 0.0274....
What is the area of a circle with a circumference of 33 units?
Circumference = 2 pi R = 33R = 33 / (2 pi)Area = pi R2 = pi (33)2 / (2 pi)2= (33)2 / (4 pi) = 86.66 square units
