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Finding the Fourth Proportional to 999.54, 1,380.17 and 645.64

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Solution

The fourth proportional to 999.54, 1,380.17 and 645.64 is: 891.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    999.54 : 1,380.17 = 645.64 : x
  2. Step 2: Convert to fraction form
    999.54/1,380.17 = 645.64/x
  3. Step 3: Cross multiply
    999.54x = 1,380.17 × 645.64
  4. Step 4: Simplify right side
    999.54x = 891,091.12
  5. Step 5: Solve for x
    x = 891,091.12/999.54
  6. Step 6: Final answer
    x = 891.50

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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.