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Finding the Fourth Proportional to 103.87, 155.60 and 78.15

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Solution

The fourth proportional to 103.87, 155.60 and 78.15 is: 117.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.87 : 155.60 = 78.15 : x
  2. Step 2: Convert to fraction form
    103.87/155.60 = 78.15/x
  3. Step 3: Cross multiply
    103.87x = 155.60 × 78.15
  4. Step 4: Simplify right side
    103.87x = 12,160.14
  5. Step 5: Solve for x
    x = 12,160.14/103.87
  6. Step 6: Final answer
    x = 117.07

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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.