Question

Please help:

Answer 1

I assume you've done solving similar figures by using proportions or ratio ?

Answer 2

proportions?

Answer 3

right

http://www.mathwarehouse.com/geometry/similar/triangles/geometric-mean.php <--- notice the SIMILAR triangles

Answer 4

proportions or ratios, that is
dividing corresponding sides on both similar shapes

Answer 5

but i only have two numbers? how am i supposed to make a proportion out of those two?

Answer 6

righ... one sec

Answer 7

ok

Answer 8

see the similar triangles ? see the corresponding sides ?

Answer 9

can you get a proportion or ratio from the corresponding sides?

Answer 10

so what would it be? x/12 = 3/x ?

Answer 11

yeap

Answer 12

i still dont know what to do from there :(