- AG and AH are tangent to a circle with center O
- =>AG=AH
Proof
- AG and AH are tangent to a circle with center O <=>∠AHO=∠AGO= π/2
- OH=OG=r => O is at the same distance of AH and AG
- => O in on the angle bissector of ΔGAH
- => ∠GAO=∠HAO
- =>ΔOAG and ΔOAH have 2 equal angles (∠GAO=∠HAO and ∠AHO=∠AGO)
- =>∠AOG=∠AOH
- =>ΔOAG is congruent to ΔOAH
- =>AG=AH