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Finding the Fourth Proportional to 938.08, 1,295.10 and 643.78

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Solution

The fourth proportional to 938.08, 1,295.10 and 643.78 is: 888.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    938.08 : 1,295.10 = 643.78 : x
  2. Step 2: Convert to fraction form
    938.08/1,295.10 = 643.78/x
  3. Step 3: Cross multiply
    938.08x = 1,295.10 × 643.78
  4. Step 4: Simplify right side
    938.08x = 833,749.78
  5. Step 5: Solve for x
    x = 833,749.78/938.08
  6. Step 6: Final answer
    x = 888.79

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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.