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Finding the Fourth Proportional to 78.86, 118.96 and 76.34

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Solution

The fourth proportional to 78.86, 118.96 and 76.34 is: 115.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.86 : 118.96 = 76.34 : x
  2. Step 2: Convert to fraction form
    78.86/118.96 = 76.34/x
  3. Step 3: Cross multiply
    78.86x = 118.96 × 76.34
  4. Step 4: Simplify right side
    78.86x = 9,081.41
  5. Step 5: Solve for x
    x = 9,081.41/78.86
  6. Step 6: Final answer
    x = 115.16

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.