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Finding the Fourth Proportional to 78.05, 117.15 and 69.43

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Solution

The fourth proportional to 78.05, 117.15 and 69.43 is: 104.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.05 : 117.15 = 69.43 : x
  2. Step 2: Convert to fraction form
    78.05/117.15 = 69.43/x
  3. Step 3: Cross multiply
    78.05x = 117.15 × 69.43
  4. Step 4: Simplify right side
    78.05x = 8,133.72
  5. Step 5: Solve for x
    x = 8,133.72/78.05
  6. Step 6: Final answer
    x = 104.21

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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.