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Finding the Fourth Proportional to 1,138.28, 1,570.80 and 640.96

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Solution

The fourth proportional to 1,138.28, 1,570.80 and 640.96 is: 884.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,138.28 : 1,570.80 = 640.96 : x
  2. Step 2: Convert to fraction form
    1,138.28/1,570.80 = 640.96/x
  3. Step 3: Cross multiply
    1,138.28x = 1,570.80 × 640.96
  4. Step 4: Simplify right side
    1,138.28x = 1,006,819.97
  5. Step 5: Solve for x
    x = 1,006,819.97/1,138.28
  6. Step 6: Final answer
    x = 884.51

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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.