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Finding the Fourth Proportional to 947.85, 1,421.75 and 399.89

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Solution

The fourth proportional to 947.85, 1,421.75 and 399.89 is: 599.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    947.85 : 1,421.75 = 399.89 : x
  2. Step 2: Convert to fraction form
    947.85/1,421.75 = 399.89/x
  3. Step 3: Cross multiply
    947.85x = 1,421.75 × 399.89
  4. Step 4: Simplify right side
    947.85x = 568,540.16
  5. Step 5: Solve for x
    x = 568,540.16/947.85
  6. Step 6: Final answer
    x = 599.82

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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.