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Finding the Fourth Proportional to 399.50, 551.30 and 288.80

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Solution

The fourth proportional to 399.50, 551.30 and 288.80 is: 398.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    399.50 : 551.30 = 288.80 : x
  2. Step 2: Convert to fraction form
    399.50/551.30 = 288.80/x
  3. Step 3: Cross multiply
    399.50x = 551.30 × 288.80
  4. Step 4: Simplify right side
    399.50x = 159,215.44
  5. Step 5: Solve for x
    x = 159,215.44/399.50
  6. Step 6: Final answer
    x = 398.54

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.