Answer:
[tex]x=\sqrt{30}[/tex]
Step-by-step explanation:
Use the geometric mean to solve for x. The side x is common to both the triangle that has the base of 3 and the triangle that has a base of 3 + 7, so x is the geometric mean. Set up that proportion as follows:
[tex]\frac{3}{x}=\frac{x}{10}[/tex] and
[tex]x^2=30[/tex] so
[tex]x=\sqrt{30}[/tex]
