Math, asked by darwintejdarwin3439, 7 months ago

ADP and ABQ are tangents to the circle, centre O. C lies on the circumference of the circle. Giving reasons for all the statements you make, work out angles DCO, CBO, OCB and BCD, all in terms of x. Hence, work out the obtuse angle DOB and prove that y = 2x

Answers

Answered by noahchappellelgie
10

Answer: I have attached a screenshot of the answer. If you are unable to open it or would rather be able to copy the answer- it is:

DCO=x (base angles in an isosceles are equal)

CBO=90-2x (radius meets tangent at 90 degrees)

OCB=90-2x (base angles in an isosceles are equal)

BCD=90-2x+x=90-x

DOB=180-2x (angles at the centre are double angles at the circumference)

Y=360-90-90-(180-2x)

Y=2x

Step-by-step explanation:

If you would like any more help or require any more reasoning as to how to solve this problem then just say so. If you copy it word for word you should get full marks (as seen in screenshot).

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Answered by amitnrw
3

Given : ADP and ABQ are tangents to the circle, centre O  

To Find : work out angles DCO, CBO, OCB and BCD, all in terms of x

obtuse angle DOB and prove that y = 2x

Solution:

∠CBO = 180° - 90 - 2x  = 90° - 2x

∠CBO = 90° - 2x

∠BCO = ∠CBO   as OB = OC = Radius

∠BCO = 90° - 2x = ∠OCB

∠DCO = ∠CDO  OC = OD = Radius

=> ∠DCO =  x

∠BCD  = ∠BCO  + ∠DCO

= 90° - 2x + x

= 90° - x

∠BCD  = 90° - x

∠DOB = 2∠BCD

=> ∠DOB = 2(90° - x)

=> ∠DOB = 180° - 2x

180° - 2x  + 90° + 90° + y =  360°   ( sum of angles of Quadrilateral)

=> -2x + y = 0

=> y = 2x

QED

Hence proved

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