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Finding the Fourth Proportional to 988.31, 1,363.10 and 638.39

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Solution

The fourth proportional to 988.31, 1,363.10 and 638.39 is: 880.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    988.31 : 1,363.10 = 638.39 : x
  2. Step 2: Convert to fraction form
    988.31/1,363.10 = 638.39/x
  3. Step 3: Cross multiply
    988.31x = 1,363.10 × 638.39
  4. Step 4: Simplify right side
    988.31x = 870,189.41
  5. Step 5: Solve for x
    x = 870,189.41/988.31
  6. Step 6: Final answer
    x = 880.48

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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.