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Finding the Fourth Proportional to 172.71, 259.11 and 86.11

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Solution

The fourth proportional to 172.71, 259.11 and 86.11 is: 129.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    172.71 : 259.11 = 86.11 : x
  2. Step 2: Convert to fraction form
    172.71/259.11 = 86.11/x
  3. Step 3: Cross multiply
    172.71x = 259.11 × 86.11
  4. Step 4: Simplify right side
    172.71x = 22,311.96
  5. Step 5: Solve for x
    x = 22,311.96/172.71
  6. Step 6: Final answer
    x = 129.19

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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.