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Finding the Fourth Proportional to 1,138.20, 1,570.57 and 640.89

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Solution

The fourth proportional to 1,138.20, 1,570.57 and 640.89 is: 884.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,138.20 : 1,570.57 = 640.89 : x
  2. Step 2: Convert to fraction form
    1,138.20/1,570.57 = 640.89/x
  3. Step 3: Cross multiply
    1,138.20x = 1,570.57 × 640.89
  4. Step 4: Simplify right side
    1,138.20x = 1,006,562.61
  5. Step 5: Solve for x
    x = 1,006,562.61/1,138.20
  6. Step 6: Final answer
    x = 884.35

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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.