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Finding the Fourth Proportional to 999.78, 1,378.44 and 747.78

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Solution

The fourth proportional to 999.78, 1,378.44 and 747.78 is: 1,031.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    999.78 : 1,378.44 = 747.78 : x
  2. Step 2: Convert to fraction form
    999.78/1,378.44 = 747.78/x
  3. Step 3: Cross multiply
    999.78x = 1,378.44 × 747.78
  4. Step 4: Simplify right side
    999.78x = 1,030,769.86
  5. Step 5: Solve for x
    x = 1,030,769.86/999.78
  6. Step 6: Final answer
    x = 1,031.00

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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.