WAEC - Mathematics (1991 - No. 29)

In the diagram above, ATR is a tangent at the point T to the circle center O, if ∠TOB = 145°, find ∠TAO

20^o

35^o

45^o

55^o

65^o

From the figure, < ATO = 90°

< AOT = 180° - 145° = 35°

\(\therefore\) < TAO = 180° - (90° + 35°)

= 55° (sum of angle in a triangle)