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Finding the Fourth Proportional to 86.76, 130.13 and 78.66

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Solution

The fourth proportional to 86.76, 130.13 and 78.66 is: 117.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.76 : 130.13 = 78.66 : x
  2. Step 2: Convert to fraction form
    86.76/130.13 = 78.66/x
  3. Step 3: Cross multiply
    86.76x = 130.13 × 78.66
  4. Step 4: Simplify right side
    86.76x = 10,236.03
  5. Step 5: Solve for x
    x = 10,236.03/86.76
  6. Step 6: Final answer
    x = 117.98

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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.