24/69 as a percentage is 34.78%. This number tells you how much of a whole the fraction represents when you look at it in terms of hundredths.
The fraction 24/69 can be thought of as a little more than one third, since one third is about 33.33%. When you write it as a percent, the value becomes easier to compare with other percentages you might see in everyday life.
Using the percent form is handy for quick estimates, like figuring out a discount, a test score, or a portion of a group. Knowing that 24/69 is 34.78% lets you see the size of the part at a glance.