What is the value of q?

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Step-by-step explanation:riangles QST and RST are similar.  Therefore, the following is true:

q       s

--- =   This results in 10q=rs.

r      10

Also, since RST is a right triangle, 4^2 + s^2 = q^2.

Since QST is also a right triangle, s^2 + 10^2 = r^2.  

           4      s

Also:   =    which leads to s^2 = 40

           s      10

Because of this, 4^2 + s^2 = q^2 becomes 16 + 40 = 56 = q^2

Then q = sqrt(56) = sqrt(4)*sqrt(14) = 2*sqrt(14) (answer)

hope it helps