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Finding the Fourth Proportional to 389.72, 584.78 and 287.18

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Solution

The fourth proportional to 389.72, 584.78 and 287.18 is: 430.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    389.72 : 584.78 = 287.18 : x
  2. Step 2: Convert to fraction form
    389.72/584.78 = 287.18/x
  3. Step 3: Cross multiply
    389.72x = 584.78 × 287.18
  4. Step 4: Simplify right side
    389.72x = 167,937.12
  5. Step 5: Solve for x
    x = 167,937.12/389.72
  6. Step 6: Final answer
    x = 430.92

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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.