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Finding the Fourth Proportional to 399.80, 551.72 and 225.15

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Solution

The fourth proportional to 399.80, 551.72 and 225.15 is: 310.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    399.80 : 551.72 = 225.15 : x
  2. Step 2: Convert to fraction form
    399.80/551.72 = 225.15/x
  3. Step 3: Cross multiply
    399.80x = 551.72 × 225.15
  4. Step 4: Simplify right side
    399.80x = 124,215.87
  5. Step 5: Solve for x
    x = 124,215.87/399.80
  6. Step 6: Final answer
    x = 310.70

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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.