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Category: Geometry

Question-63324

Question Number 63324 by pradyot_pathak last updated on 02/Jul/19 Answered by Hope last updated on 02/Jul/19 $${area}\:{of}\:{pentagon}=\frac{\mathrm{1}}{\mathrm{4}}×\mathrm{5}×\mathrm{12}^{\mathrm{2}} ×{cot}\left(\frac{\mathrm{180}^{{o}} }{\mathrm{5}}\right) \\ $$$$=\mathrm{180}×{cot}\mathrm{36}^{{o}} \\ $$$${external}\:{angle}=\frac{\mathrm{360}^{{o}} }{\mathrm{5}}=\mathrm{72}^{{o}} \\…

Prove-that-e-i-1-e-i-2-e-i-2-

Question Number 128805 by bramlexs22 last updated on 10/Jan/21 $$\:\mathrm{Prove}\:\mathrm{that}\:\mathrm{e}^{\mathrm{i}\theta} +\mathrm{1}\:=\:\mathrm{e}^{−\frac{\mathrm{i}\theta}{\mathrm{2}}} \:+\:\mathrm{e}^{\frac{\mathrm{i}\theta}{\mathrm{2}}} \:? \\ $$ Commented by mr W last updated on 10/Jan/21 $${LHS}=\left(\mathrm{1}+\mathrm{cos}\:\theta\right)+{i}\:\mathrm{sin}\:\theta \\…

Question-128764

Question Number 128764 by behi83417@gmail.com last updated on 10/Jan/21 Commented by behi83417@gmail.com last updated on 10/Jan/21 $$\measuredangle\mathrm{DAB}=\measuredangle\mathrm{CBA}=\mathrm{30}^{\bullet} \\ $$$$\:\:\:\:\:\:\:\:\:\:\:\:\:\:\boldsymbol{\mathrm{AB}}=? \\ $$ Answered by Olaf last…

Question-63194

Question Number 63194 by lalitchand last updated on 30/Jun/19 Answered by mr W last updated on 30/Jun/19 $$\frac{\Delta{AQR}}{\Delta{ABC}}=\left(\frac{{AQ}}{{AB}}\right)^{\mathrm{2}} =\left(\frac{\mathrm{2}}{\mathrm{3}}\right)^{\mathrm{2}} =\frac{\mathrm{4}}{\mathrm{9}} \\ $$$$\frac{\Delta{APS}}{\Delta{ABC}}=\left(\frac{{AP}}{{AB}}\right)^{\mathrm{2}} =\left(\frac{\mathrm{1}}{\mathrm{3}}\right)^{\mathrm{2}} =\frac{\mathrm{1}}{\mathrm{9}} \\…