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Finding the Fourth Proportional to 687.72, 949.39 and 478.07

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Solution

The fourth proportional to 687.72, 949.39 and 478.07 is: 659.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.72 : 949.39 = 478.07 : x
  2. Step 2: Convert to fraction form
    687.72/949.39 = 478.07/x
  3. Step 3: Cross multiply
    687.72x = 949.39 × 478.07
  4. Step 4: Simplify right side
    687.72x = 453,872.50
  5. Step 5: Solve for x
    x = 453,872.50/687.72
  6. Step 6: Final answer
    x = 659.96

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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.