Revision work on chord properties of circle

A chord of a circle is a line segment joining two points on its circumference. A chord which is not  a diameter  divides the circumference into two arcs of different sizes

 Major Arc

To find Radius, use Cosine

Cos 45 =4/r

R Cos 45 =4

R = 4/Cos 45 = 4/0.7071 =5.65

Further reading:

ESSENTIAL MATHEMATICS FOR SENIOR SECONDARY SCHOOLS BOOK 2

EXERCISE 10.2; NO 1, 3, and 5