Simplify (3r^2+4) (2r-1).-8r^3+6r^2
1 answer:
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Answer:
i. Curved surface area = 2310
ii. Total surface area = 3696
iii. volume = 12936
Step-by-step explanation:
Perimeter of the circular base = circumference of the circle = 132 cm
circumference of a circle = 2r
132 = 2r
r =
=
r = 66 x
= 3 x 7
= 21
radius = 21 cm
vertical height, h = 28 cm
Thus applying the Pythagoras theorem,
=
+
= +
= 784 + 441
= 1225
l =
l = 35 cm
The slant height is 35 cm.
i. Curved surface area = rl
= x 21 x 35
= 22 x 3 x 35
= 2310
curved surface area of the cone is 2310 .
ii. Total surface area = +
rl
= r(r + l)
= x 21 (21 + 35)
= 22 x 3 x 56
= 3696
The total surface area of the cone is 3696 .
iii. volume of a cone = h
= x
x
x 28
= 12936
The volume of the cone is 12936
There is only one repeating number, so we multiply both sides by
Now subtract the original number we had to both sides, which is the same as
So we have:
Divide 9 to both sides:
Multiply the fraction by 10 to get rid of the decimal in the numerator.
Simplify the fraction by dividing the numerator and denominator by 2: