the total surface area of a solid cylinder is 968cm^2.if the curved surface is 660cm^2. find the radius
Answers
Answer: aprox 15 cm
Step-by-step explanation:
The equation for the surface area of a cylinder is 2Πrh x 2Πr2. We'll have two equations and two unknowns to solve this equation
Since the surface area is 968, we'll have 968 = 2Πrh x 2Πr2
If the curved surface area is 660, then we know that 2Πrh = 660.
Substitute that 660 into the first equation and get:
968 = 660 x 2Πr2
308 = 2Πr2
154 = Πr2
49.02 = r2
7.002 = r, or approximately 7 cm
If r is 7 and 2∏rh = 660, then
660 = 2∏(7)h
660 = 14∏h
15.006 = h, or approximately 15cm
Total surface area of a cylinder i= 2Πrh x 2Πr2.
Concept
We have given value of curved surface area, we will put value in total surface area.
Solution:
Since the total surface area is 968cm^2 , we'll have 968 cm^2 = 2Πrh x 2Πr2
If the curved surface area is 660cm^2 , then we know that 2Πrh = 660cm^2.
Put value of Curved surface area in t.S.A
968 = 660 x 2Πr2
308 = 2Πr2
154 = Πr2
49.02 = r2
7.002 = radius , or approximately 7 cm
r is 7 and 2∏rh = 660, then
660 = 2∏(7)h
660 = 14∏h
15.006 = height
Hence r = 7cm approx.
H = 15cm approx.