step-by-step explanation: 0.75*4.5=3.375
the normal distribution is symmetric about its mean.
so answer c) must be true.
the angle = 144 degrees.
look at it this way (it is a proportion question)
30 people would require a pie chart made of a full circle (360 degrees)
12 people would require x part of the pie chart.
30/360 = 12 / x cross multiply
30x = 360 * 12 simplify the right
30x = 4320 divide by 30
30x/30 = 4320/20
x = 144 answer