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Finding the Fourth Proportional to 85,403.60, 128,105.40 and 81,321.20

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Solution

The fourth proportional to 85,403.60, 128,105.40 and 81,321.20 is: 121,981.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    85,403.60 : 128,105.40 = 81,321.20 : x
  2. Step 2: Convert to fraction form
    85,403.60/128,105.40 = 81,321.20/x
  3. Step 3: Cross multiply
    85,403.60x = 128,105.40 × 81,321.20
  4. Step 4: Simplify right side
    85,403.60x = 10,417,684,854.48
  5. Step 5: Solve for x
    x = 10,417,684,854.48/85,403.60
  6. Step 6: Final answer
    x = 121,981.80

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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.