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Finding the Fourth Proportional to 86.26, 129.65 and 79.90

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Solution

The fourth proportional to 86.26, 129.65 and 79.90 is: 120.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.26 : 129.65 = 79.90 : x
  2. Step 2: Convert to fraction form
    86.26/129.65 = 79.90/x
  3. Step 3: Cross multiply
    86.26x = 129.65 × 79.90
  4. Step 4: Simplify right side
    86.26x = 10,358.76
  5. Step 5: Solve for x
    x = 10,358.76/86.26
  6. Step 6: Final answer
    x = 120.08

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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.