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Finding the Fourth Proportional to 100.86, 139.17 and 56.60

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Solution

The fourth proportional to 100.86, 139.17 and 56.60 is: 78.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.86 : 139.17 = 56.60 : x
  2. Step 2: Convert to fraction form
    100.86/139.17 = 56.60/x
  3. Step 3: Cross multiply
    100.86x = 139.17 × 56.60
  4. Step 4: Simplify right side
    100.86x = 7,877.02
  5. Step 5: Solve for x
    x = 7,877.02/100.86
  6. Step 6: Final answer
    x = 78.10

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.