Law of Cosines

${a}^{2}={b}^{2}+{c}^{2}-2bc\phantom{\rule{thinmathspace}{0ex}}cos\alpha$

${b}^{2}={a}^{2}+{c}^{2}-2ac\phantom{\rule{thinmathspace}{0ex}}cos\beta$

${c}^{2}={a}^{2}+{b}^{2}-2ab\phantom{\rule{thinmathspace}{0ex}}cos\gamma$

Keywords: Law of Cosines