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Finding the Fourth Proportional to 78.11, 107.62 and 61.73

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Solution

The fourth proportional to 78.11, 107.62 and 61.73 is: 85.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.11 : 107.62 = 61.73 : x
  2. Step 2: Convert to fraction form
    78.11/107.62 = 61.73/x
  3. Step 3: Cross multiply
    78.11x = 107.62 × 61.73
  4. Step 4: Simplify right side
    78.11x = 6,643.07
  5. Step 5: Solve for x
    x = 6,643.07/78.11
  6. Step 6: Final answer
    x = 85.05

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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.