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Finding the Fourth Proportional to 999.10, 1,378.76 and 557

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Solution

The fourth proportional to 999.10, 1,378.76 and 557 is: 768.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    999.10 : 1,378.76 = 557 : x
  2. Step 2: Convert to fraction form
    999.10/1,378.76 = 557/x
  3. Step 3: Cross multiply
    999.10x = 1,378.76 × 557
  4. Step 4: Simplify right side
    999.10x = 767,969.32
  5. Step 5: Solve for x
    x = 767,969.32/999.10
  6. Step 6: Final answer
    x = 768.66

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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.