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Finding the Fourth Proportional to 86.59, 129.79 and 77.59

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Solution

The fourth proportional to 86.59, 129.79 and 77.59 is: 116.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.59 : 129.79 = 77.59 : x
  2. Step 2: Convert to fraction form
    86.59/129.79 = 77.59/x
  3. Step 3: Cross multiply
    86.59x = 129.79 × 77.59
  4. Step 4: Simplify right side
    86.59x = 10,070.41
  5. Step 5: Solve for x
    x = 10,070.41/86.59
  6. Step 6: Final answer
    x = 116.30

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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.