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Finding the Fourth Proportional to 614.80, 921.40 and 285.70

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Solution

The fourth proportional to 614.80, 921.40 and 285.70 is: 428.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    614.80 : 921.40 = 285.70 : x
  2. Step 2: Convert to fraction form
    614.80/921.40 = 285.70/x
  3. Step 3: Cross multiply
    614.80x = 921.40 × 285.70
  4. Step 4: Simplify right side
    614.80x = 263,243.98
  5. Step 5: Solve for x
    x = 263,243.98/614.80
  6. Step 6: Final answer
    x = 428.18

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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.