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Finding the Fourth Proportional to 78.13, 107.67 and 69.40

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Solution

The fourth proportional to 78.13, 107.67 and 69.40 is: 95.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.13 : 107.67 = 69.40 : x
  2. Step 2: Convert to fraction form
    78.13/107.67 = 69.40/x
  3. Step 3: Cross multiply
    78.13x = 107.67 × 69.40
  4. Step 4: Simplify right side
    78.13x = 7,472.30
  5. Step 5: Solve for x
    x = 7,472.30/78.13
  6. Step 6: Final answer
    x = 95.64

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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.