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Finding the Fourth Proportional to 280.54, 420.78 and 75.13

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Solution

The fourth proportional to 280.54, 420.78 and 75.13 is: 112.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.54 : 420.78 = 75.13 : x
  2. Step 2: Convert to fraction form
    280.54/420.78 = 75.13/x
  3. Step 3: Cross multiply
    280.54x = 420.78 × 75.13
  4. Step 4: Simplify right side
    280.54x = 31,610.72
  5. Step 5: Solve for x
    x = 31,610.72/280.54
  6. Step 6: Final answer
    x = 112.68

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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.