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Finding the Fourth Proportional to 839.76, 1,257.81 and 406

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Solution

The fourth proportional to 839.76, 1,257.81 and 406 is: 608.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    839.76 : 1,257.81 = 406 : x
  2. Step 2: Convert to fraction form
    839.76/1,257.81 = 406/x
  3. Step 3: Cross multiply
    839.76x = 1,257.81 × 406
  4. Step 4: Simplify right side
    839.76x = 510,670.86
  5. Step 5: Solve for x
    x = 510,670.86/839.76
  6. Step 6: Final answer
    x = 608.12

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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.