Find the length arc of DB. Leave your answer in terms of pi.
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Length of arc DB = 14 π feet
Solution:
Radius AB = 18 feet
DC is the diameter of the circle.
∠CAB = 40°
Sum of the adjacent angles in a straight line = 180°
m∠DAB + m∠CAB = 180°
m∠DAB + 40° = 180°
Subtract 40° from both sides.
m∠DAB = 140°
To find the length of arc DB:
[tex]$\text{Arc length} =2 \pi r\left(\frac{\theta}{360}\right)[/tex]
[tex]$ =2 \pi \times 18\left(\frac{140^\circ}{360}\right)[/tex]
[tex]$ =2 \pi \left(\frac{140^\circ}{20}\right)[/tex]
= [tex]14\pi[/tex] feet
Length of arc DB = 14 π feet