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Help!!!
A, C and D are points on a circle, centre 0.
AB and CB are tangents to the circle.
Angle ABC = 74°
Work out the size of angle ADC.
Show your working clearly.

Help A C and D are points on a circle centre 0 AB and CB are tangents to the circle Angle ABC 74 Work out the size of angle ADC Show your working clearly class=

Respuesta :

Answer:

∠ ADC = 53°

Step-by-step explanation:

Note the angle between the radius and the tangent is 90°

The sum of the angles in quadrilateral AOCB = 360°, thus

∠ AOC = 360° - (90 + 90 + 74 )° = 360° - 254° = 106°

∠ AOC is twice the angle on the circumference ∠ ADC, thus

∠ ADC = 106° ÷ 2 = 53°

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