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Finding the Fourth Proportional to 172.83, 259.31 and 86.15

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Solution

The fourth proportional to 172.83, 259.31 and 86.15 is: 129.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    172.83 : 259.31 = 86.15 : x
  2. Step 2: Convert to fraction form
    172.83/259.31 = 86.15/x
  3. Step 3: Cross multiply
    172.83x = 259.31 × 86.15
  4. Step 4: Simplify right side
    172.83x = 22,339.13
  5. Step 5: Solve for x
    x = 22,339.13/172.83
  6. Step 6: Final answer
    x = 129.25

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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.