Triangle DEF is equilateral. Find AE.
DA = 3, AF = 2
Find AE.
Hello magenta!
Cosine law:\(c^2=a^2+b^2-2ab\ cos\ \gamma\)
\(\overline{AE}\ ^2=3^2+5^2-2\cdot 3\cdot 5\cdot cos\ 60^{\circ}\\ \overline{AE}=\sqrt{9+25-30\cdot \frac{1}{2}}=\sqrt{19}\\ \color{blue}\overline{AE}=4.359\)
!
!
