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Finding the Fourth Proportional to 988.30, 1,363.83 and 638.99

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Solution

The fourth proportional to 988.30, 1,363.83 and 638.99 is: 881.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    988.30 : 1,363.83 = 638.99 : x
  2. Step 2: Convert to fraction form
    988.30/1,363.83 = 638.99/x
  3. Step 3: Cross multiply
    988.30x = 1,363.83 × 638.99
  4. Step 4: Simplify right side
    988.30x = 871,473.73
  5. Step 5: Solve for x
    x = 871,473.73/988.30
  6. Step 6: Final answer
    x = 881.80

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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.