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Finding the Fourth Proportional to 389.15, 583.65 and 129.15

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Solution

The fourth proportional to 389.15, 583.65 and 129.15 is: 193.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    389.15 : 583.65 = 129.15 : x
  2. Step 2: Convert to fraction form
    389.15/583.65 = 129.15/x
  3. Step 3: Cross multiply
    389.15x = 583.65 × 129.15
  4. Step 4: Simplify right side
    389.15x = 75,378.40
  5. Step 5: Solve for x
    x = 75,378.40/389.15
  6. Step 6: Final answer
    x = 193.70

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.