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Finding the Fourth Proportional to 923.20, 1,378.95 and 869.90

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Solution

The fourth proportional to 923.20, 1,378.95 and 869.90 is: 1,299.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    923.20 : 1,378.95 = 869.90 : x
  2. Step 2: Convert to fraction form
    923.20/1,378.95 = 869.90/x
  3. Step 3: Cross multiply
    923.20x = 1,378.95 × 869.90
  4. Step 4: Simplify right side
    923.20x = 1,199,548.61
  5. Step 5: Solve for x
    x = 1,199,548.61/923.20
  6. Step 6: Final answer
    x = 1,299.34

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.