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Finding the Fourth Proportional to 1,218.56, 1,679.86 and 868.64

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Solution

The fourth proportional to 1,218.56, 1,679.86 and 868.64 is: 1,197.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,218.56 : 1,679.86 = 868.64 : x
  2. Step 2: Convert to fraction form
    1,218.56/1,679.86 = 868.64/x
  3. Step 3: Cross multiply
    1,218.56x = 1,679.86 × 868.64
  4. Step 4: Simplify right side
    1,218.56x = 1,459,198.17
  5. Step 5: Solve for x
    x = 1,459,198.17/1,218.56
  6. Step 6: Final answer
    x = 1,197.48

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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.