Question-211323

Question Number 211323 by mr W last updated on 06/Sep/24

Commented by mr W last updated on 06/Sep/24

$${both}\:{circles}\:{are}\:{concentric}. \\ $$$${find}\:\angle{C}=? \\ $$

Answered by liuxinnan last updated on 06/Sep/24

(1/2)∠DCA=∠OCA=∠OAC=(1/2)∠DAC=(o/2) ∠B=π−∠BAC−∠DCA=π−3o

$$\frac{\mathrm{1}}{\mathrm{2}}\angle{DCA}=\angle{OCA}=\angle{OAC}=\frac{\mathrm{1}}{\mathrm{2}}\angle{DAC}=\frac{{o}}{\mathrm{2}} \\ $$$$\angle{B}=\pi−\angle{BAC}−\angle{DCA}=\pi−\mathrm{3}{o} \\ $$

Commented by liuxinnan last updated on 06/Sep/24

Commented by mr W last updated on 06/Sep/24

$${in}\:{the}\:{figure}\:“{o}''\:{is}\:{just}\:{a}\:{symbol} \\ $$$${indicating}\:{that}\:{the}\:{two}\:{red}\:{angles}\: \\ $$$${are}\:{equal}.\:“{o}''\:{is}\:{not}\:{a}\:{given}\:{value}. \\ $$

Commented by liuxinnan last updated on 06/Sep/24