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Finding the Fourth Proportional to 399.66, 551.37 and 312.60

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Solution

The fourth proportional to 399.66, 551.37 and 312.60 is: 431.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    399.66 : 551.37 = 312.60 : x
  2. Step 2: Convert to fraction form
    399.66/551.37 = 312.60/x
  3. Step 3: Cross multiply
    399.66x = 551.37 × 312.60
  4. Step 4: Simplify right side
    399.66x = 172,358.26
  5. Step 5: Solve for x
    x = 172,358.26/399.66
  6. Step 6: Final answer
    x = 431.26

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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.