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Finding the Fourth Proportional to 801.78, 1,105.12 and 644.16

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Solution

The fourth proportional to 801.78, 1,105.12 and 644.16 is: 887.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    801.78 : 1,105.12 = 644.16 : x
  2. Step 2: Convert to fraction form
    801.78/1,105.12 = 644.16/x
  3. Step 3: Cross multiply
    801.78x = 1,105.12 × 644.16
  4. Step 4: Simplify right side
    801.78x = 711,874.10
  5. Step 5: Solve for x
    x = 711,874.10/801.78
  6. Step 6: Final answer
    x = 887.87

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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.