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Finding the Fourth Proportional to 399.28, 598.86 and 142.78

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Solution

The fourth proportional to 399.28, 598.86 and 142.78 is: 214.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    399.28 : 598.86 = 142.78 : x
  2. Step 2: Convert to fraction form
    399.28/598.86 = 142.78/x
  3. Step 3: Cross multiply
    399.28x = 598.86 × 142.78
  4. Step 4: Simplify right side
    399.28x = 85,505.23
  5. Step 5: Solve for x
    x = 85,505.23/399.28
  6. Step 6: Final answer
    x = 214.15

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.