Home / 431.91-647.79-139.41

Finding the Fourth Proportional to 431.91, 647.79 and 139.41

Calculator

Solution

The fourth proportional to 431.91, 647.79 and 139.41 is: 209.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.91 : 647.79 = 139.41 : x
  2. Step 2: Convert to fraction form
    431.91/647.79 = 139.41/x
  3. Step 3: Cross multiply
    431.91x = 647.79 × 139.41
  4. Step 4: Simplify right side
    431.91x = 90,308.40
  5. Step 5: Solve for x
    x = 90,308.40/431.91
  6. Step 6: Final answer
    x = 209.09

Related Problems

Find fourth proportional to 215.96, 323.90 and 69.71
Half scale
Find fourth proportional to 863.82, 1,295.58 and 278.82
Double scale
Find fourth proportional to 432.91, 649.29 and 140.41
Similar ratio
Find fourth proportional to 647.87, 971.69 and 209.12
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.