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Finding the Fourth Proportional to 1,211.38, 1,817.72 and 938

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Solution

The fourth proportional to 1,211.38, 1,817.72 and 938 is: 1,407.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,211.38 : 1,817.72 = 938 : x
  2. Step 2: Convert to fraction form
    1,211.38/1,817.72 = 938/x
  3. Step 3: Cross multiply
    1,211.38x = 1,817.72 × 938
  4. Step 4: Simplify right side
    1,211.38x = 1,705,021.36
  5. Step 5: Solve for x
    x = 1,705,021.36/1,211.38
  6. Step 6: Final answer
    x = 1,407.51

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.