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Finding the Fourth Proportional to 78.18, 107.81 and 76.51

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Solution

The fourth proportional to 78.18, 107.81 and 76.51 is: 105.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.18 : 107.81 = 76.51 : x
  2. Step 2: Convert to fraction form
    78.18/107.81 = 76.51/x
  3. Step 3: Cross multiply
    78.18x = 107.81 × 76.51
  4. Step 4: Simplify right side
    78.18x = 8,248.16
  5. Step 5: Solve for x
    x = 8,248.16/78.18
  6. Step 6: Final answer
    x = 105.51

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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.