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Finding the Fourth Proportional to 999.71, 1,380.33 and 645.83

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Solution

The fourth proportional to 999.71, 1,380.33 and 645.83 is: 891.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    999.71 : 1,380.33 = 645.83 : x
  2. Step 2: Convert to fraction form
    999.71/1,380.33 = 645.83/x
  3. Step 3: Cross multiply
    999.71x = 1,380.33 × 645.83
  4. Step 4: Simplify right side
    999.71x = 891,462.75
  5. Step 5: Solve for x
    x = 891,462.75/999.71
  6. Step 6: Final answer
    x = 891.72

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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.