find the lateral area of the cylinder

#15

Question

find the lateral area of the cylinder

#15

highschoolmom2010 · Answer

attachment

phi · Answer

the lateral area is the area of the curved part of the cylinder.

phi · Answer

This gives the equation.

highschoolmom2010 · Answer

$$LA=2\pi r*h$$

phi · Answer

in question 15, it looks like the diameter is 6
that means the radius is 3

highschoolmom2010 · Answer

thats what my book says as the formula

phi · Answer

yes, that is the formula.  You need to replace r with the length of the radius and replace "h" with the "height" given by the picture.

phi · Answer

I would just put in the numbers.  what do you get ?

highschoolmom2010 · Answer

$$LA=2 \pi(3*9)$$
$$LA=2 \pi 27$$

phi · Answer

yes.  when you multiply, you can change the order so
2π27= 2*27*π
and you can simplify it a little more
54π

that may be the answer (it is exact)
or if you use π is about 3.14, you can multiply it out more. Depends on what way they want the answer.

highschoolmom2010 · Answer

i put that in to calculator and got
LA= 169.646003294

phi · Answer

the instructions say "to the nearest whole number"
so round to the nearest integer.

highschoolmom2010 · Answer

LA=170

phi · Answer

yes

highschoolmom2010 · Answer

horray @phi thanks