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Finding the Fourth Proportional to 280.71, 421.05 and 75.28

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Solution

The fourth proportional to 280.71, 421.05 and 75.28 is: 112.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.71 : 421.05 = 75.28 : x
  2. Step 2: Convert to fraction form
    280.71/421.05 = 75.28/x
  3. Step 3: Cross multiply
    280.71x = 421.05 × 75.28
  4. Step 4: Simplify right side
    280.71x = 31,694.54
  5. Step 5: Solve for x
    x = 31,694.54/280.71
  6. Step 6: Final answer
    x = 112.91

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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.