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Finding the Fourth Proportional to 687.81, 949.23 and 393.18

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Solution

The fourth proportional to 687.81, 949.23 and 393.18 is: 542.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.81 : 949.23 = 393.18 : x
  2. Step 2: Convert to fraction form
    687.81/949.23 = 393.18/x
  3. Step 3: Cross multiply
    687.81x = 949.23 × 393.18
  4. Step 4: Simplify right side
    687.81x = 373,218.25
  5. Step 5: Solve for x
    x = 373,218.25/687.81
  6. Step 6: Final answer
    x = 542.62

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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.