Step-by-step explanation:
[tex] \tan(45) = \frac{7}{a} [/tex]
[tex]1 = \frac{7}{a} [/tex]
[tex]a = 7[/tex]
[tex]b = \sqrt{ {7}^{2} + {7}^{2} } [/tex]
[tex]b = \sqrt{49 + 49} = \sqrt{98} = 7 \sqrt{2} [/tex]
