Ответ:

[tex]sin (\alpha ) = \frac{96}{100}[/tex]

Объяснение:

[tex]sin^{2} (\alpha )+cos^{2} (\alpha) = 1\\\\sin^{2} (\alpha )+(\frac{28}{100} )^{2} = 1\\\\sin^{2} (\alpha ) = 1-(\frac{28}{100})^{2}\\\\sin (\alpha ) = \sqrt{1-\frac{784}{10000}}\\\\sin (\alpha ) = \sqrt{\frac{10000-784}{10000}}\\\\sin (\alpha ) = \sqrt{\frac{9216}{10000}}\\\\sin (\alpha ) = \sqrt{\frac{96^{2} }{100^{2} } } \\\\sin (\alpha ) = \frac{96}{100}[/tex]