Percentage is expressed in terms of 100
For the first part,
70/100 shows 70% as a ratio
For the second part,
if the whole is represented by x, then the ratio, 84/x compares 84 to the whole, x
To solve for x, it becomes
70/100 = 84/x
by cross multiplying, it becomes
70x = 84 * 100 = 8400
x = 8400/70
x = 100 l