tolong dibantu. please

[tex]a = \sqrt{12^{2} + 15 ^{2} } \\ = \sqrt{144 + 225} \\ = \sqrt{369} \\ = 19.2 \\ \\ b = \sqrt{8 ^{2} - 6 ^{2} } \\ = \sqrt{64 - 36} \\ = \sqrt{28} \\ = 5.3[/tex]