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Finding the Fourth Proportional to 354.95, 488.65 and 311.21

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Solution

The fourth proportional to 354.95, 488.65 and 311.21 is: 428.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    354.95 : 488.65 = 311.21 : x
  2. Step 2: Convert to fraction form
    354.95/488.65 = 311.21/x
  3. Step 3: Cross multiply
    354.95x = 488.65 × 311.21
  4. Step 4: Simplify right side
    354.95x = 152,072.77
  5. Step 5: Solve for x
    x = 152,072.77/354.95
  6. Step 6: Final answer
    x = 428.43

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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.