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Finding the Fourth Proportional to 999.56, 1,378.88 and 645.36

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Solution

The fourth proportional to 999.56, 1,378.88 and 645.36 is: 890.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    999.56 : 1,378.88 = 645.36 : x
  2. Step 2: Convert to fraction form
    999.56/1,378.88 = 645.36/x
  3. Step 3: Cross multiply
    999.56x = 1,378.88 × 645.36
  4. Step 4: Simplify right side
    999.56x = 889,874.00
  5. Step 5: Solve for x
    x = 889,874.00/999.56
  6. Step 6: Final answer
    x = 890.27

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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.