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Finding the Fourth Proportional to 939.06, 1,294.65 and 643.95

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Solution

The fourth proportional to 939.06, 1,294.65 and 643.95 is: 887.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    939.06 : 1,294.65 = 643.95 : x
  2. Step 2: Convert to fraction form
    939.06/1,294.65 = 643.95/x
  3. Step 3: Cross multiply
    939.06x = 1,294.65 × 643.95
  4. Step 4: Simplify right side
    939.06x = 833,689.87
  5. Step 5: Solve for x
    x = 833,689.87/939.06
  6. Step 6: Final answer
    x = 887.79

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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.