Question

Ley de cosenos
Paso a paso por fa​

Answer 1

${b}^{2} = {a}^{2} + {c}^{2} - 2ac(cos \beta ) \\ {b}^{2} = {18}^{2} + {21}^{2} - 2(18)(21)(cos23) \\ {b}^{2} = 324 + 441 - 756(0.92) \\ {b}^{2} =765 - 695.52 \\ {b}^{2} = 69.48 \\ b = \sqrt{69.48} \\ b = 8.33$