18. The radii of two concentric circles are 13cma tangent to the small

1.	18. The radii of two concentric circles are 13cma tangent to the smaller circle touching it aircles are 13cm and 8cm. AB is tangent of a bigger Circle. BD ist D. Find the length of AB
Answer» from right triangle BOD BD = √(OB²-OD²) = √(13²- 8²) = √105 from right triangle POD PD = √(OP²-OD²) = √(13²-8²) = √105 PB = BD + PD = 2√105 PB²= 420 from right triangle APB AP = √(AB²- PB²) =√26²- 420 = √676-420 = √256 = 16

18. The radii of two concentric circles are 13cma tangent to the smaller circle touching it aircles are 13cm and 8cm. AB is tangent of a bigger Circle. BD ist D. Find the length of AB

Answer»

from right triangle BOD

BD = √(OB²-OD²) = √(13²- 8²) = √105

from right triangle POD

PD = √(OP²-OD²) = √(13²-8²) = √105

PB = BD + PD = 2√105 PB²= 420

from right triangle APB

AP = √(AB²- PB²) =√26²- 420 = √676-420 = √256 = 16