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Finding the Fourth Proportional to 399.87, 551.03 and 315.72

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Solution

The fourth proportional to 399.87, 551.03 and 315.72 is: 435.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    399.87 : 551.03 = 315.72 : x
  2. Step 2: Convert to fraction form
    399.87/551.03 = 315.72/x
  3. Step 3: Cross multiply
    399.87x = 551.03 × 315.72
  4. Step 4: Simplify right side
    399.87x = 173,969.61
  5. Step 5: Solve for x
    x = 173,969.61/399.87
  6. Step 6: Final answer
    x = 435.07

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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.