Answer
$b\approx7.6, A\approx67^\circ, C\approx23^\circ$
Work Step by Step
Step 1. Based on the given conditions, using the Pythagorean Theorem, we have
$b=\sqrt {a^2+c^2}=\sqrt {7^2+3^2}=\sqrt {58}\approx7.6$
Step 2. For angle $A$, in the right triangle, we have
$tanA=\frac{a}{c}=\frac{7}{3}$, thus $A=tan^{-1}(\frac{7}{3})\approx67^\circ$
Step 3. We can find the angle as
$C=90^\circ-67^\circ=23^\circ$
Step 4. We solved the triangle with
$b\approx7.6, A\approx67^\circ, C\approx23^\circ$
