If D is the degree of the curve of radius R, the exact length of its specified chord, is

Diameter of the curve × cosine of half the degree

Radius of the curve × sine of half the degree

Diameter of the curve × sine of half the degree

Diameter of the curve × tangent of half the degree

If D is the degree of the curve of radius R, the exact length of its s

1.	If D is the degree of the curve of radius R, the exact length of its specified chord, is
A.	Radius of the curve × sine of half the degree
B.	Diameter of the curve × sine of half the degree
C.	Diameter of the curve × cosine of half the degree
D.	Diameter of the curve × tangent of half the degree
Answer» C. Diameter of the curve × cosine of half the degree