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Finding the Fourth Proportional to 801.70, 1,105.05 and 643.75

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Solution

The fourth proportional to 801.70, 1,105.05 and 643.75 is: 887.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    801.70 : 1,105.05 = 643.75 : x
  2. Step 2: Convert to fraction form
    801.70/1,105.05 = 643.75/x
  3. Step 3: Cross multiply
    801.70x = 1,105.05 × 643.75
  4. Step 4: Simplify right side
    801.70x = 711,375.94
  5. Step 5: Solve for x
    x = 711,375.94/801.70
  6. Step 6: Final answer
    x = 887.33

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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.