Find Radius of a Cylinder of given surface area and height

Surface Area of a cylinder is 603 cm2. If the height of this cylinder is 10 cm, find its radius.

[Wheelie]

You can also find the answer without guessing if you use the prime factoring method and treat the expression like a quadratic.
If: 0 = r^2 + 10r - 96, with the appropriate prime factors we can find that (16r - 6r) can replace (10r) in this quadratic.
If you factor by grouping, you will arrive at y=(r-6)(r+16).
When we find the zeroes of this expression,  we can ignore -16 because our radius must be positive, leaving us with an answer of positive 6.

[idrisdhanwala]

Thanku so much sir!!! Strategy is best!!!!👏👏👏👏

[chlyeri]

This is easier than using the quadratic formula to find the radius. Thank you

[modjadjidineo]

Thank you very much i understand much better❤

[katerinademartel]

Thank you so much!! Your voice makes it interesting to watch and listen:)

[e-stauf]

bro u just singlehandedly saved my grade thanks again

[hananalabdulkareem]

btw i saw your brother in the construction site yesterday, he says hi and bring him chai

[vivaanrajpurohit]

what if you don't know about the quadratic equations and your answer is in decimals?

[jaoum]

How do you work out a question on cylinders that says "find the area of the metal that would be needed to make the tank.

[jayGee]

what if it was 39.78=r^2+6(r) ? and the number is not 3 which = 27 and not 4 which = 40?

[adarshdwivedi]

Well done sir for uploading this video

[hananalabdulkareem]

very good video, just please put deodorant

[yeetirosina]

Hold up, this is the same equation as in my homework..