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Finding the Fourth Proportional to 1,115.98, 1,540.22 and 643.79

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Solution

The fourth proportional to 1,115.98, 1,540.22 and 643.79 is: 888.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,115.98 : 1,540.22 = 643.79 : x
  2. Step 2: Convert to fraction form
    1,115.98/1,540.22 = 643.79/x
  3. Step 3: Cross multiply
    1,115.98x = 1,540.22 × 643.79
  4. Step 4: Simplify right side
    1,115.98x = 991,567.31
  5. Step 5: Solve for x
    x = 991,567.31/1,115.98
  6. Step 6: Final answer
    x = 888.52

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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.