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Finding the Fourth Proportional to 687.96, 949.08 and 408.21

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Solution

The fourth proportional to 687.96, 949.08 and 408.21 is: 563.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.96 : 949.08 = 408.21 : x
  2. Step 2: Convert to fraction form
    687.96/949.08 = 408.21/x
  3. Step 3: Cross multiply
    687.96x = 949.08 × 408.21
  4. Step 4: Simplify right side
    687.96x = 387,423.95
  5. Step 5: Solve for x
    x = 387,423.95/687.96
  6. Step 6: Final answer
    x = 563.15

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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.