Answer:
28 cm
Explanation:
We can write a similarity statement to help us:
TUV ~ LMN
TU corresponds to LM; this gives us the ratio
8/x
TV corresponds to LN; this gives us the ratio
6/21
Together, they give us the proportion
8/x = 6/21
Cross multiplying, we have
8(21) = x(6)
168 = 6x
Divide both sides by 6:
168/6 = 6x/6
28 = x