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Finding the Fourth Proportional to 78.20, 116.45 and 75.09

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Solution

The fourth proportional to 78.20, 116.45 and 75.09 is: 111.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.20 : 116.45 = 75.09 : x
  2. Step 2: Convert to fraction form
    78.20/116.45 = 75.09/x
  3. Step 3: Cross multiply
    78.20x = 116.45 × 75.09
  4. Step 4: Simplify right side
    78.20x = 8,744.23
  5. Step 5: Solve for x
    x = 8,744.23/78.20
  6. Step 6: Final answer
    x = 111.82

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.