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In-any-ABC-if-the-angles-are-in-the-ratio-1-2-3-then-the-ratio-of-corresponding-sides-is-




Question Number 113807 by deepraj123 last updated on 15/Sep/20
In any △ABC, if the angles are in   the ratio 1 : 2 : 3, then the ratio of  corresponding sides is
$$\mathrm{In}\:\mathrm{any}\:\bigtriangleup{ABC},\:\mathrm{if}\:\mathrm{the}\:\mathrm{angles}\:\mathrm{are}\:\mathrm{in}\: \\ $$$$\mathrm{the}\:\mathrm{ratio}\:\mathrm{1}\::\:\mathrm{2}\::\:\mathrm{3},\:\mathrm{then}\:\mathrm{the}\:\mathrm{ratio}\:\mathrm{of} \\ $$$$\mathrm{corresponding}\:\mathrm{sides}\:\mathrm{is} \\ $$
Answered by bemath last updated on 15/Sep/20
∠A = k ,∠B=2k ,∠C=3k  ⇒ 6k=180° →k=30°   (a/(sin 30°))=(b/(sin 60°))=(c/(sin 90°))  (a/(1/2))=(b/((1/2)(√3)))=(c/1) →  { ((b=(1/2)(√3) c)),((a=(1/2)c)) :}  a : b : c = (1/2) : (1/2)(√3) : 1                  = 1 : (√3) : 2
$$\angle{A}\:=\:{k}\:,\angle{B}=\mathrm{2}{k}\:,\angle{C}=\mathrm{3}{k} \\ $$$$\Rightarrow\:\mathrm{6}{k}=\mathrm{180}°\:\rightarrow{k}=\mathrm{30}° \\ $$$$\:\frac{{a}}{\mathrm{sin}\:\mathrm{30}°}=\frac{{b}}{\mathrm{sin}\:\mathrm{60}°}=\frac{{c}}{\mathrm{sin}\:\mathrm{90}°} \\ $$$$\frac{{a}}{\frac{\mathrm{1}}{\mathrm{2}}}=\frac{{b}}{\frac{\mathrm{1}}{\mathrm{2}}\sqrt{\mathrm{3}}}=\frac{{c}}{\mathrm{1}}\:\rightarrow\:\begin{cases}{{b}=\frac{\mathrm{1}}{\mathrm{2}}\sqrt{\mathrm{3}}\:{c}}\\{{a}=\frac{\mathrm{1}}{\mathrm{2}}{c}}\end{cases} \\ $$$${a}\::\:{b}\::\:{c}\:=\:\frac{\mathrm{1}}{\mathrm{2}}\::\:\frac{\mathrm{1}}{\mathrm{2}}\sqrt{\mathrm{3}}\::\:\mathrm{1}\: \\ $$$$\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:=\:\mathrm{1}\::\:\sqrt{\mathrm{3}}\::\:\mathrm{2} \\ $$$$ \\ $$

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