8 The diagram shows four identical spheres placed between two wooden blocks on a ruler.
4
A
sphere
bo
0 5
What is the diameter of one sphere?
1.0 cm
B 2.0 cm

10
16
C 3.0cm
wooden block
15 cm
D 4.0cm
9
A length of cotton thread is measured between two points on a ruler as
shown in the figure below
When the length of the thread was wound closely around a pen, it goes round
six times as shown in the second figure below.