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Finding the Fourth Proportional to 386.91, 581.31 and 318.51

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Solution

The fourth proportional to 386.91, 581.31 and 318.51 is: 478.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    386.91 : 581.31 = 318.51 : x
  2. Step 2: Convert to fraction form
    386.91/581.31 = 318.51/x
  3. Step 3: Cross multiply
    386.91x = 581.31 × 318.51
  4. Step 4: Simplify right side
    386.91x = 185,153.05
  5. Step 5: Solve for x
    x = 185,153.05/386.91
  6. Step 6: Final answer
    x = 478.54

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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.