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Finding the Fourth Proportional to 399.74, 552.29 and 311.58

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Solution

The fourth proportional to 399.74, 552.29 and 311.58 is: 430.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    399.74 : 552.29 = 311.58 : x
  2. Step 2: Convert to fraction form
    399.74/552.29 = 311.58/x
  3. Step 3: Cross multiply
    399.74x = 552.29 × 311.58
  4. Step 4: Simplify right side
    399.74x = 172,080.96
  5. Step 5: Solve for x
    x = 172,080.96/399.74
  6. Step 6: Final answer
    x = 430.49

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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.