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Finding the Fourth Proportional to 78.31, 108.30 and 68.59

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Solution

The fourth proportional to 78.31, 108.30 and 68.59 is: 94.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.31 : 108.30 = 68.59 : x
  2. Step 2: Convert to fraction form
    78.31/108.30 = 68.59/x
  3. Step 3: Cross multiply
    78.31x = 108.30 × 68.59
  4. Step 4: Simplify right side
    78.31x = 7,428.30
  5. Step 5: Solve for x
    x = 7,428.30/78.31
  6. Step 6: Final answer
    x = 94.86

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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.