Answer:
[tex] x = \sqrt{30} [/tex]
Step-by-step explanation:
BD is the altitude of the right ∆ which divides the hypotenuse to create two line segments, CD, and AD.
According to the right triangle altitude theorem,
[tex] BD = \sqrt{CD*AD} [/tex]
CD = 3, AD = 7, therefore,
[tex] BD = \sqrt{3*7} [/tex]
[tex] BD = \sqrt{21} [/tex]
Find x using Pythagorean theorem
[tex] x^2 = BD^2 + CD^2 [/tex]
[tex] x^2 = (\sqrt{21})^2 + 3^2 [/tex]
[tex] x^2 = 21 + 9 [/tex]
[tex] x^2 = 30 [/tex]
[tex] x = \sqrt{30} [/tex]
