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Finding the Fourth Proportional to 939.70, 1,294.14 and 815.32

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Solution

The fourth proportional to 939.70, 1,294.14 and 815.32 is: 1,122.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    939.70 : 1,294.14 = 815.32 : x
  2. Step 2: Convert to fraction form
    939.70/1,294.14 = 815.32/x
  3. Step 3: Cross multiply
    939.70x = 1,294.14 × 815.32
  4. Step 4: Simplify right side
    939.70x = 1,055,138.22
  5. Step 5: Solve for x
    x = 1,055,138.22/939.70
  6. Step 6: Final answer
    x = 1,122.85

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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.