How do you use proportions to solve percent problems

Step-by-step explanation:

EXAMPLE #1:

What number is 75% of 4?   (or   Find 75% of 4.)

The PERCENT always goes over 100.

   (It's a part of the whole 100%.)

4 appears with the word of:

   It's the WHOLE and goes on the bottom.

A proportion showing one fraction  with PART as the numerator and 4 as the denominator equal to another fraction with 75 as the numerator and 100 as the denominator.

We're trying to find the missing PART (on the top).

In a proportion the cross-products are equal:   So 4 times 75 is equal to 100 times the PART.

The missing PART equals 4 times 75 divided by 100.

(Multiply the two opposite corners with numbers; then divide by the other number.)

4 times 75=100 times the part

300=100 times the part

300/100=100/100 times the part

3=   the part

A proportion showing the denominator,  4, times the diagonally opposite 75; divided by  100.

f(x) has value 150 at x= 0

and 0 at x= 3

so d(f(x))/dt = slope = -150/3 = -50

nothjing

step-by-step explanation: