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Finding the Fourth Proportional to 988.05, 1,363.48 and 638.74

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Solution

The fourth proportional to 988.05, 1,363.48 and 638.74 is: 881.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    988.05 : 1,363.48 = 638.74 : x
  2. Step 2: Convert to fraction form
    988.05/1,363.48 = 638.74/x
  3. Step 3: Cross multiply
    988.05x = 1,363.48 × 638.74
  4. Step 4: Simplify right side
    988.05x = 870,909.22
  5. Step 5: Solve for x
    x = 870,909.22/988.05
  6. Step 6: Final answer
    x = 881.44

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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.