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Finding the Fourth Proportional to 311.02, 428.20 and 290.36

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Solution

The fourth proportional to 311.02, 428.20 and 290.36 is: 399.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.02 : 428.20 = 290.36 : x
  2. Step 2: Convert to fraction form
    311.02/428.20 = 290.36/x
  3. Step 3: Cross multiply
    311.02x = 428.20 × 290.36
  4. Step 4: Simplify right side
    311.02x = 124,332.15
  5. Step 5: Solve for x
    x = 124,332.15/311.02
  6. Step 6: Final answer
    x = 399.76

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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.