The the surface area of a cylinder with radius R and height H is twice the product of Pi and the square of the radius plus twice
the product the pie, the radius, and the height
1 answer:
Concept:
(1) Curved surface area of cylinder = Circumference of the base × Height of cylinder
(2) Area of the base = Area of circle = π × (radius)²
(3) Circumference of the base = 2×π× (radius)
Consider a right circular cylinder as given in attached figure
Its height (AB) = H
Its radius (OC) = R
Now, we shall calculate the curved surface area of the cylinder (CSA)
(CSA) = Circumference of the base × Height of cylinder
(CSA) = 2×π×R × H = 2πRH -------(i)
Again, we shall calculate the area of the top and bottom circles
Area of the top and bottom (A) = 2× Area of circle
(A) =2×[ π × (radius)²]
or, (A) = 2×π×R² = 2πR²------------(ii)
Now, we shall calculate the surface area or total surface area of the cylinder.
SA = CSA + A
SA = 2πRH + 2πR²
or, SA = 2πR² + 2πRH
This is the required equation.
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After two quarters:
$4331.16 + ($4331.16 × 0.048) = $4359.06
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There's another way that uses less calculation, but more algebra. I call it the exponential formula method! There's this general formula for stuff that increases exponentially, like virus, population, and MONEY:
M is money, d is deposit, t is time taken, and c is just some unknown constant related to the interest rate. There's also the natural logarithm form of this equation, which will come in handy later:
Alright first we gotta find that constant c for this equation to be useful! Let's plug in stuff we know.
We know how much she'll have after one quarter (0.25 years), and we know how much she deposited initially.
After pressing some buttons on the calculator we'll find that c = 0.1875.
Great! Now we can use that formula to find how many years (t) it'll take to reach M=$8000. To save time I'm going to use the natural log form:
That will give us t = 3.522 which means it'll take approximately 3.5 years for her deposit to reach $8000!