Home / 411.20-616.80-388.80

Finding the Fourth Proportional to 411.20, 616.80 and 388.80

Calculator

Solution

The fourth proportional to 411.20, 616.80 and 388.80 is: 583.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    411.20 : 616.80 = 388.80 : x
  2. Step 2: Convert to fraction form
    411.20/616.80 = 388.80/x
  3. Step 3: Cross multiply
    411.20x = 616.80 × 388.80
  4. Step 4: Simplify right side
    411.20x = 239,811.84
  5. Step 5: Solve for x
    x = 239,811.84/411.20
  6. Step 6: Final answer
    x = 583.20

Related Problems

Find fourth proportional to 205.60, 308.40 and 194.40
Half scale
Find fourth proportional to 822.40, 1,233.60 and 777.60
Double scale
Find fourth proportional to 412.20, 618.30 and 389.80
Similar ratio
Find fourth proportional to 616.80, 925.20 and 583.20
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.