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Finding the Fourth Proportional to 1,112.40, 1,668.69 and 381.78

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Solution

The fourth proportional to 1,112.40, 1,668.69 and 381.78 is: 572.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,112.40 : 1,668.69 = 381.78 : x
  2. Step 2: Convert to fraction form
    1,112.40/1,668.69 = 381.78/x
  3. Step 3: Cross multiply
    1,112.40x = 1,668.69 × 381.78
  4. Step 4: Simplify right side
    1,112.40x = 637,072.47
  5. Step 5: Solve for x
    x = 637,072.47/1,112.40
  6. Step 6: Final answer
    x = 572.70

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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.