If the ratio of girls to boys in the education program is 5 to 1, this means that for every 5 girls, there is 1 boy.
Let's call the number of girls "5x" (since there are 5 girls for every 1 boy) and the number of boys "x".
According to the problem, the total number of students in the education program is 90:
5x + x = 90
Simplifying and solving for "x", we get:
6x = 90
x = 15
Now that we know the value of "x", we can find the number of girls by multiplying by 5:
5x = 5(15) = 75
Therefore, there are 75 girls in the education program.