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Finding the Fourth Proportional to 687.90, 949.29 and 393.16

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Solution

The fourth proportional to 687.90, 949.29 and 393.16 is: 542.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.90 : 949.29 = 393.16 : x
  2. Step 2: Convert to fraction form
    687.90/949.29 = 393.16/x
  3. Step 3: Cross multiply
    687.90x = 949.29 × 393.16
  4. Step 4: Simplify right side
    687.90x = 373,222.86
  5. Step 5: Solve for x
    x = 373,222.86/687.90
  6. Step 6: Final answer
    x = 542.55

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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.