Triscia P. answered • 03/16/16
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The two triangles are similar which means their sides are proportionate w/ each other....so set up a proportion for each of the unknown sides.
Triangle PQR is similar to Triangle LMN, which means
side PQ is similar to side LM
side QR is similar to side MN
side RP is similar to side NL
The only pair of sides we actually have values for are QR and MN.
Use this "known" pair as the start of your proportion...
20/15 = y/12 Cross multiply...
15y = 240
15y/15 = 240/15
y = 16 This means side PQ is 16
Use the same "known" pair to set up the next proportionate.
20/15 = x/18 Cross multiply...
15x = 360
15x/15 = 360/15
x = 24 This means side RP is 24
Hope this helps!
