Length of an Arc
Construct the point B' on the circle c so that the size of an angle BAB' is 76°.
Hint
Use tool 
for construction an angle with given size. To measure arc length use circular arc 
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for construction an angle with given size. To measure arc length use circular arc . The length of an arc of a circle with radius 3 cm if the arc subtends a central angle of 72° is
Let r is radius of the circle and a is central angle. Write the formula for arc length BB'.