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Finding the Fourth Proportional to 389.65, 584.29 and 139.40

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Solution

The fourth proportional to 389.65, 584.29 and 139.40 is: 209.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    389.65 : 584.29 = 139.40 : x
  2. Step 2: Convert to fraction form
    389.65/584.29 = 139.40/x
  3. Step 3: Cross multiply
    389.65x = 584.29 × 139.40
  4. Step 4: Simplify right side
    389.65x = 81,449.33
  5. Step 5: Solve for x
    x = 81,449.33/389.65
  6. Step 6: Final answer
    x = 209.03

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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.