I'm using the formula for surface area of a cylinder: 2(Pi)r^2 +2(Pi)rh.
Question asks: tin of height 6cm has surface area 54(pi)cm^2 find radius.
So I first created this quadratic: 2(Pi)r^2 + 12(Pi)r = 54(Pi)cm^2
Then 2(Pi)r^2 + 12(Pi)r - 54(Pi)cm2 = 0
Not sure how to go from here. Does one use substitution or use the Pi +coefficient as 'a' and 'b' in the quadratic formula ax^2 + bX +c =0
No need to do the whole thing for me-I jsut need a nudge.
Thanks
Question asks: tin of height 6cm has surface area 54(pi)cm^2 find radius.
So I first created this quadratic: 2(Pi)r^2 + 12(Pi)r = 54(Pi)cm^2
Then 2(Pi)r^2 + 12(Pi)r - 54(Pi)cm2 = 0
Not sure how to go from here. Does one use substitution or use the Pi +coefficient as 'a' and 'b' in the quadratic formula ax^2 + bX +c =0
No need to do the whole thing for me-I jsut need a nudge.
Thanks