Final answer:
To find 65% of 90, you can use the proportion a) 65/100 = x/90.
Step-by-step explanation:
To find 65% of 90, you can set up a proportion using the given information:
a) 65/100 = x/90
Cross-multiply and solve for x:
65 * 90 = 100 * x
x = 58.5
Therefore, the proportion that can be used to find 65% of 90 is a) 65/100 = x/90