Home / 321.20-481.80-199.40

Finding the Fourth Proportional to 321.20, 481.80 and 199.40

Calculator

Solution

The fourth proportional to 321.20, 481.80 and 199.40 is: 299.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    321.20 : 481.80 = 199.40 : x
  2. Step 2: Convert to fraction form
    321.20/481.80 = 199.40/x
  3. Step 3: Cross multiply
    321.20x = 481.80 × 199.40
  4. Step 4: Simplify right side
    321.20x = 96,070.92
  5. Step 5: Solve for x
    x = 96,070.92/321.20
  6. Step 6: Final answer
    x = 299.10

Related Problems

Find fourth proportional to 160.60, 240.90 and 99.70
Half scale
Find fourth proportional to 642.40, 963.60 and 398.80
Double scale
Find fourth proportional to 322.20, 483.30 and 200.40
Similar ratio
Find fourth proportional to 481.80, 722.70 and 299.10
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.