Question Number 183124 by HeferH last updated on 21/Dec/22
Answered by a.lgnaoui last updated on 22/Dec/22
$$\mathrm{methode}\:\mathrm{1}\left(\mathrm{simple}\right) \\ $$$$\bigtriangleup\mathrm{ABC}\:\:\:\:\mathrm{30}+\mathrm{50}+\mathrm{x}+\theta=\mathrm{180} \\ $$$$\mathrm{x}+\theta=\mathrm{100} \\ $$$$\mathrm{AB}\parallel\mathrm{DE}\:\:\:\Rightarrow\measuredangle\mathrm{CDE}=\measuredangle\mathrm{CBA}=\mathrm{100} \\ $$$$\measuredangle\mathrm{EDF}=\measuredangle\mathrm{DAB}=\mathrm{20}\Rightarrow\measuredangle\mathrm{FDB}=\mathrm{60} \\ $$$$\bigtriangleup\mathrm{EBC}\:\mathrm{triangle}\:\mathrm{isocele}\:\left(\:\mathrm{BE}=\mathrm{EC}\right) \\ $$$$\measuredangle\mathrm{FBD}=\measuredangle\mathrm{ECD}=\mathrm{50}\:\:\:\Rightarrow\theta=\mathrm{50} \\ $$$$\:\:\:\:\:\:\:\:\:\mathrm{x}=\mathrm{100}−\mathrm{50}=\mathrm{50} \\ $$$$ \\ $$
Commented by a.lgnaoui last updated on 22/Dec/22
Commented by mr W last updated on 22/Dec/22
$${how}\:{can}\:{you}\:{say} \\ $$$$\bigtriangleup\mathrm{EBC}\:\mathrm{triangle}\:\mathrm{isocele}\:\left(\:\mathrm{BE}=\mathrm{EC}\right)? \\ $$
Commented by a.lgnaoui last updated on 22/Dec/22
$${par}\:{mesure} \\ $$
Commented by mr W last updated on 23/Dec/22
$${why}\:{don}'{t}\:{you}\:{directly}\:{use}\:{a}\:{protractor} \\ $$$${to}\:{messure}\:{the}\:{angle}? \\ $$$${then}\:{you}\:{don}'{t}\:{need}\:{to}\:{do}\:{all}\:{the}\:{other} \\ $$$${unnecessary}\:{calculations}\:{you}\:{did}. \\ $$
Commented by mr W last updated on 23/Dec/22
