Home / 813.20-1,220-265.41

Finding the Fourth Proportional to 813.20, 1,220 and 265.41

Calculator

Solution

The fourth proportional to 813.20, 1,220 and 265.41 is: 398.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.20 : 1,220 = 265.41 : x
  2. Step 2: Convert to fraction form
    813.20/1,220 = 265.41/x
  3. Step 3: Cross multiply
    813.20x = 1,220 × 265.41
  4. Step 4: Simplify right side
    813.20x = 323,800.20
  5. Step 5: Solve for x
    x = 323,800.20/813.20
  6. Step 6: Final answer
    x = 398.18

Related Problems

Find fourth proportional to 406.60, 610 and 132.71
Half scale
Find fourth proportional to 1,626.40, 2,440 and 530.82
Double scale
Find fourth proportional to 814.20, 1,221.50 and 266.41
Similar ratio
Find fourth proportional to 1,219.80, 1,830 and 398.12
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.