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Finding the Fourth Proportional to 938.89, 1,294.46 and 643.64

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Solution

The fourth proportional to 938.89, 1,294.46 and 643.64 is: 887.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    938.89 : 1,294.46 = 643.64 : x
  2. Step 2: Convert to fraction form
    938.89/1,294.46 = 643.64/x
  3. Step 3: Cross multiply
    938.89x = 1,294.46 × 643.64
  4. Step 4: Simplify right side
    938.89x = 833,163.02
  5. Step 5: Solve for x
    x = 833,163.02/938.89
  6. Step 6: Final answer
    x = 887.40

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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.