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Finding the Fourth Proportional to 643.66, 888.51 and 394.90

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Solution

The fourth proportional to 643.66, 888.51 and 394.90 is: 545.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.66 : 888.51 = 394.90 : x
  2. Step 2: Convert to fraction form
    643.66/888.51 = 394.90/x
  3. Step 3: Cross multiply
    643.66x = 888.51 × 394.90
  4. Step 4: Simplify right side
    643.66x = 350,872.60
  5. Step 5: Solve for x
    x = 350,872.60/643.66
  6. Step 6: Final answer
    x = 545.12

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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.