Question

A liquid filter shaped as a right circular cone is shown below.



If a similar cone has a slant height of 15 cm, what is its lateral area?

90π cm2

150π cm2

75π cm2

120π cm2

Answer 1

20/8 = 15/x
20x = 120
x = 6

lateral area = pi . r . l
= pi . 6. 15
= 90 pi cm2

Answer 2

120cm^2

Answer 3

lateral area=1/2CL
=1/2(2pi)(8)(15)
=120

Answer 4

circumference of a circle=2pi r or pi.diameter

Answer 5

how did she get 90?

Answer 6

lol... cornitodisc from where you got that formula ?
and why are you using it for bigger cone ?
Read the question once. They are asking to find the lateral area of smaller cone. Not the bigger one.

Answer 7

The circumference of a circle is the length around it. The circumference of a circle can be calculated from its diameter using the formula:

Circumference of a circle = 2*pi*radius

or


Circumference of a circle = pi*diameter

where r is the radius and d is the diameter of the circle, and π (the Greek letter pi) is defined as the ratio of the circumference of the circle to its diameter.

(the numerical value of pi is 3.141 592 653 589 793...).

Read more: http://wiki.answers.com/Q/What_is_the_formula_for_the_circumference_of_a_circle#ixzz1zgK4l72d
yes,it is,but the changes of the question is only the slant height but not its radius.right?