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Finding the Fourth Proportional to 1,218.78, 1,828.17 and 640.98

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Solution

The fourth proportional to 1,218.78, 1,828.17 and 640.98 is: 961.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,218.78 : 1,828.17 = 640.98 : x
  2. Step 2: Convert to fraction form
    1,218.78/1,828.17 = 640.98/x
  3. Step 3: Cross multiply
    1,218.78x = 1,828.17 × 640.98
  4. Step 4: Simplify right side
    1,218.78x = 1,171,820.41
  5. Step 5: Solve for x
    x = 1,171,820.41/1,218.78
  6. Step 6: Final answer
    x = 961.47

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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.