WAEC - Mathematics (2001 - No. 39)
A chord of length 30cm is 8cm away from the center of the circle. What is the radius of the circle? Take \(\pi =\frac{22}{7}\)
16cm
17cm
18cm
20cm
คำอธิบาย
From the diagram
\(r^2 = B^2 + 15^2\\
= 64 + 225\\
r = \sqrt{289} = 17cm\)