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Finding the Fourth Proportional to 389.12, 583.70 and 115.20

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Solution

The fourth proportional to 389.12, 583.70 and 115.20 is: 172.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    389.12 : 583.70 = 115.20 : x
  2. Step 2: Convert to fraction form
    389.12/583.70 = 115.20/x
  3. Step 3: Cross multiply
    389.12x = 583.70 × 115.20
  4. Step 4: Simplify right side
    389.12x = 67,241.66
  5. Step 5: Solve for x
    x = 67,241.66/389.12
  6. Step 6: Final answer
    x = 172.81

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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.