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Finding the Fourth Proportional to 486.99, 726.94 and 428.61

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Solution

The fourth proportional to 486.99, 726.94 and 428.61 is: 639.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    486.99 : 726.94 = 428.61 : x
  2. Step 2: Convert to fraction form
    486.99/726.94 = 428.61/x
  3. Step 3: Cross multiply
    486.99x = 726.94 × 428.61
  4. Step 4: Simplify right side
    486.99x = 311,573.75
  5. Step 5: Solve for x
    x = 311,573.75/486.99
  6. Step 6: Final answer
    x = 639.79

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.