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Question-212982




Question Number 212982 by Spillover last updated on 27/Oct/24
Answered by ajfour last updated on 28/Oct/24
2r=((85)/3)
$$\mathrm{2}{r}=\frac{\mathrm{85}}{\mathrm{3}}\:\: \\ $$
Answered by A5T last updated on 27/Oct/24
(1/2)×a×bsin(90+θ)=((abc)/(4R)) where a=(√(8^2 +15^2 ))=17  c=(√(20^2 +15^2 ))=25;sin(90+θ)=((15)/(17))  ⇒R=(c/(2cosθ))=((25)/(2×((15)/(17))))=((5×17)/6)=((85)/6)  ⇒2R=((85)/3)
$$\frac{\mathrm{1}}{\mathrm{2}}×{a}×{bsin}\left(\mathrm{90}+\theta\right)=\frac{{abc}}{\mathrm{4}{R}}\:{where}\:{a}=\sqrt{\mathrm{8}^{\mathrm{2}} +\mathrm{15}^{\mathrm{2}} }=\mathrm{17} \\ $$$${c}=\sqrt{\mathrm{20}^{\mathrm{2}} +\mathrm{15}^{\mathrm{2}} }=\mathrm{25};{sin}\left(\mathrm{90}+\theta\right)=\frac{\mathrm{15}}{\mathrm{17}} \\ $$$$\Rightarrow{R}=\frac{{c}}{\mathrm{2}{cos}\theta}=\frac{\mathrm{25}}{\mathrm{2}×\frac{\mathrm{15}}{\mathrm{17}}}=\frac{\mathrm{5}×\mathrm{17}}{\mathrm{6}}=\frac{\mathrm{85}}{\mathrm{6}} \\ $$$$\Rightarrow\mathrm{2}{R}=\frac{\mathrm{85}}{\mathrm{3}} \\ $$
Commented by A5T last updated on 27/Oct/24

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