Find the missing side length of m.

Answer:
m=4
Step-by-step explanation:
Since we know that quadrilateral ABCD is similar to QRST, we know that the side lengths will be proportional to one another. As such, we should take a ratio to determine the side length of m.
[tex]\frac{ST}{CD}=\frac{RS}{BC}\\\\\frac{6}{15} =\frac{m}{10}\\[/tex]
[tex]\frac{6*10}{15} =m\\m=60/15=4[/tex]
m=4