Problem 1
V = pi*r^2*h
V = pi*70^2*50
V = 245000pi cubic cm exactly
This approximates to 769300 (since 245000*3.14 = 769300)
Use more decimal digits of pi to get a better approximation.
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Problem 2
SA = pi*r^2 + 2*pi*r*h
SA = pi*70^2 + 2*pi*70*50
SA = 11900pi square cm exactly
This approximates to 37366 because 11900*3.14 = 37366
Use more decimal digits of pi to get a better approximation.
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Problem 3
volume of the cuboid is 55*35*20 = 38500 cubic cm
The volume of water displaced is equal to the cuboid's volume.
This is because the cube's material pushes the water out of the way to make room.
The previous volume of roughly 769300 increases to about 769300+38500 = 807800
Use this new larger volume to find the new value of h.
V = pi*r^2*h
807800 = 3.14*70^2*h
h = 807800/(3.14*70^2)
h = 52.5022747952684 approximately
The new height is about 52.502 cm
This is a change of 52.502 - 50 = 2.502
The water's height has risen about 2.502 cm.
This value is approximate.