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Finding the Fourth Proportional to 947.70, 1,420.56 and 399.42

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Solution

The fourth proportional to 947.70, 1,420.56 and 399.42 is: 598.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    947.70 : 1,420.56 = 399.42 : x
  2. Step 2: Convert to fraction form
    947.70/1,420.56 = 399.42/x
  3. Step 3: Cross multiply
    947.70x = 1,420.56 × 399.42
  4. Step 4: Simplify right side
    947.70x = 567,400.08
  5. Step 5: Solve for x
    x = 567,400.08/947.70
  6. Step 6: Final answer
    x = 598.71

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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.