The more painstaking way would be to divide the spinner up into 100 pieces, and shade in 5 of those pieces. Since 5/100 = 0.05 = 5% this means that landing on any of the 5 pieces has a 5% chance of happening.
A better way to do this is to use 20 slices instead. This works because 5/100 reduces to 1/20 (divide top and bottom by 5). Instead of shading in 5 slices, Mark should shade in 1. If you use a calculator, you should see that 1/20 = 0.05 = 5% as well.
The second option is more practical but even then a spinner with 20 sections is still a lot. I think it might be better for Mark to pull random numbers out of a hat, or let the computer generate random numbers.
The best way to justify which answers are correct are to calculate the circumference and the area for each of the circles with the given radii. I organized this information into a chart.
Circumference | Area
1/2 3.14 0.785
1 6.28 3.14
1 1/2 9.42 7.065
2 12.56 12.56
2 1/2 15.7 19.625
The first three choices will result in a numerical value for the radius that is smaller than the area.
First, multiply both sides by 88, because you can divide 88 by 22. That final would be 3k*88/22 = -13. Simplified, that would be 12k = -13. Divide both sides by 12, making the final answer k = -12/13, or in decimal form 1.08333...
//Hope it helps and thanks for writing more specific.
There is an X intercept at x=-8
There is a y intercept at y=4 (0,4)