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Finding the Fourth Proportional to 78.31, 108.21 and 68.77

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Solution

The fourth proportional to 78.31, 108.21 and 68.77 is: 95.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.31 : 108.21 = 68.77 : x
  2. Step 2: Convert to fraction form
    78.31/108.21 = 68.77/x
  3. Step 3: Cross multiply
    78.31x = 108.21 × 68.77
  4. Step 4: Simplify right side
    78.31x = 7,441.60
  5. Step 5: Solve for x
    x = 7,441.60/78.31
  6. Step 6: Final answer
    x = 95.03

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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.