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Finding the Fourth Proportional to 77.68, 116.40 and 69.60

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Solution

The fourth proportional to 77.68, 116.40 and 69.60 is: 104.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.68 : 116.40 = 69.60 : x
  2. Step 2: Convert to fraction form
    77.68/116.40 = 69.60/x
  3. Step 3: Cross multiply
    77.68x = 116.40 × 69.60
  4. Step 4: Simplify right side
    77.68x = 8,101.44
  5. Step 5: Solve for x
    x = 8,101.44/77.68
  6. Step 6: Final answer
    x = 104.29

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.