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Finding the Fourth Proportional to 947.57, 1,421.28 and 399.20

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Solution

The fourth proportional to 947.57, 1,421.28 and 399.20 is: 598.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    947.57 : 1,421.28 = 399.20 : x
  2. Step 2: Convert to fraction form
    947.57/1,421.28 = 399.20/x
  3. Step 3: Cross multiply
    947.57x = 1,421.28 × 399.20
  4. Step 4: Simplify right side
    947.57x = 567,367.87
  5. Step 5: Solve for x
    x = 567,367.87/947.57
  6. Step 6: Final answer
    x = 598.76

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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.