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Finding the Fourth Proportional to 1,005.20, 1,387.10 and 563

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Solution

The fourth proportional to 1,005.20, 1,387.10 and 563 is: 776.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,005.20 : 1,387.10 = 563 : x
  2. Step 2: Convert to fraction form
    1,005.20/1,387.10 = 563/x
  3. Step 3: Cross multiply
    1,005.20x = 1,387.10 × 563
  4. Step 4: Simplify right side
    1,005.20x = 780,937.30
  5. Step 5: Solve for x
    x = 780,937.30/1,005.20
  6. Step 6: Final answer
    x = 776.90

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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.