Could someone explain to me how to fine the anwser?

In the figure below, the segment is parallel to one side of the triangle. Find the value of y

9
12
15 3/4
19

Question

Could someone explain to me how to fine the anwser?

In the figure below, the segment is parallel to one side of the triangle. Find the value of y



9
12
15 3/4
19

savannaadams16 · Answer

attachment

jdoe0001 · Answer

have you covered similaritries yet?

savannaadams16 · Answer

Yes, we have.

jdoe0001 · Answer

well, then notice|dw:1458081335914:dw|
so, just use proportiions to find "y"

thus $\cfrac{8+6}{6}=\cfrac{21}{y}$

savannaadams16 · Answer

How do you know when to add or subtract two numbers over another number?
My online book doesn't explain things very well.

jdoe0001 · Answer

"corresponding" sides

notice, 8+6 is the "left side" of the big one, so, we also use the "left" side of the small one, or 6

then we use the "base or bottom" of the big one, and then we use the base or bottom of the small one :)

corresponding sides

jdoe0001 · Answer

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