Question Number 67728 by TawaTawa last updated on 30/Aug/19
Commented by mr W last updated on 30/Aug/19
$${question}\:{is}\:{not}\:{clear}. \\ $$$${is}\:\angle{BAD}=\mathrm{90}°\:{as}\:{marked}\:{or}\:{is} \\ $$$$\angle{BAC}=\mathrm{90}°\:{as}\:{shown}? \\ $$
Commented by TawaTawa last updated on 30/Aug/19
$$\mathrm{yes}\:\mathrm{sir} \\ $$
Commented by TawaTawa last updated on 30/Aug/19
$$\angle\:\mathrm{BAD}\:=\:\mathrm{90} \\ $$
Commented by TawaTawa last updated on 30/Aug/19
$$\mathrm{That}\:\mathrm{is}\:\mathrm{how}\:\mathrm{the}\:\mathrm{question}\:\mathrm{is}.\:\mathrm{Sir}\:\mathrm{do}\:\mathrm{it}\:\mathrm{correctly}\:\mathrm{sir}.\:\:\mathrm{I}\:\mathrm{will}\:\mathrm{study} \\ $$$$\mathrm{your}\:\mathrm{work}\:\mathrm{sir} \\ $$$$ \\ $$
Commented by TawaTawa last updated on 31/Aug/19
$$\mathrm{Sir},\:\:\angle\:\mathrm{BAD}\:=\:\mathrm{90} \\ $$
Answered by mr W last updated on 31/Aug/19
Commented by mr W last updated on 31/Aug/19
$$\angle{BAD}=\mathrm{90}° \\ $$$${draw}\:{AF}//{ED} \\ $$$$\angle{ABD}=\mathrm{90}°−\alpha \\ $$$$\angle{BAF}=\mathrm{90}°−\alpha=\angle{ABD} \\ $$$${BF}={AF}={FD}=\frac{{a}}{\mathrm{2}} \\ $$$$\frac{{DC}}{{FC}}=\frac{{DE}}{{AF}} \\ $$$$\Rightarrow\frac{{a}}{\frac{{a}}{\mathrm{2}}+{a}}=\frac{\mathrm{3}}{\frac{{a}}{\mathrm{2}}} \\ $$$$\Rightarrow\frac{\mathrm{2}}{\mathrm{3}}=\frac{\mathrm{6}}{{a}} \\ $$$$\Rightarrow{a}=\mathrm{9} \\ $$$${BC}=\mathrm{2}{a}=\mathrm{18} \\ $$
Commented by TawaTawa last updated on 31/Aug/19
$$\mathrm{Great}.\:\:\mathrm{Really}\:\mathrm{appreciate}\:\mathrm{you}\:\mathrm{sir}.\:\mathrm{God}\:\mathrm{bless}\:\mathrm{you}\:\mathrm{sir}. \\ $$