Question Number 46906 by behi83417@gmail.com last updated on 02/Nov/18
Commented by behi83417@gmail.com last updated on 03/Nov/18
$${in}\:{A}\overset{\bigtriangleup} {{B}C}:\left({a},{b},{c},\:{as}\:{sides}\right) \\ $$$${D}:\:{midpoint}\:{of}\:{AC}, \\ $$$${BE}:\:{bisect}\:{of}\:\measuredangle{B},{and}\measuredangle{DBD}'. \\ $$$$\boldsymbol{{wanted}}: \\ $$$$\mathrm{1}.\boldsymbol{\mathrm{BD}}'\:\:\&\:\:\boldsymbol{\mathrm{DD}}',{in}\:{terms}\:{of}:\:{a},{b},{c}. \\ $$$$\mathrm{2}.{angle}\:{between}\::\boldsymbol{\mathrm{AC}}\:\&\:\boldsymbol{\mathrm{IK}}. \\ $$$$\mathrm{3}.{when}\:{angle}\:{of}\:\boldsymbol{\mathrm{AC}}\:\&\:\boldsymbol{\mathrm{IK}},{equales} \\ $$$${to}:\mathrm{30}^{\bullet} ,{then}:\:\measuredangle\boldsymbol{\mathrm{B}}=? \\ $$$$\mathrm{4}.{calculate}\:\measuredangle\boldsymbol{\mathrm{B}},{if}\::\boldsymbol{\mathrm{AC}}\parallel\boldsymbol{\mathrm{IK}}. \\ $$