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Answer:
[tex]\sqrt{49 - x^{2}}[/tex]
Step-by-step explanation:
Pythagorean theorem [tex]c^{2} = a^{2} + b^{2}[/tex] Then:
[tex]7^{2} = x^{2} + y^{2}\\y^{2} = 7^{2} - x^{2}\\y^{2} = 49 - x^{2}\\y = \sqrt{49 - x^{2}}[/tex]
the lenght of the third side = [tex]\sqrt{49 - x^{2}}[/tex]
Ф = [tex]sin^{-1} (\frac{x}{7} )[/tex]
Ф = [tex]cos^{-1} (\frac{y}{7} )[/tex]
Ф = [tex]tan^{-1} (\frac{x}{y} )[/tex]