PLEASE HELP A, B, C and D are points on the circumference of a circle, centre O. ED is a tangent to the circle. Angle ODB= 25degrees. Work out angle BAD. You must give a reason for each stage of your working.

angle BAD=65  degrees

Step-by-step explanation:

angle ODB=25 degrees       (given)

Draw line from O to B

OD=OB     (both are radii)

angle OBD=angle ODB    (triangle ODB is isosceles)

angle OBD=25 degrees  

angle DOB=130 degrees  (180-25-25=130, all triangles contain 180 degrees)

angle DOB is a central angle

arc DCB=130 degrees  (central angle theorem postulate: The measure of the central angle is equal to the degree measure of the intercepted arc.)

angle BAD=130/2=65 degrees  (inscribed angle theorem: The size of an inscribed angle is equal to half the size of the central angle.)

answer: 8d

step-by-step explanation:

45+5= 50+5=55+5=60