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Finding the Fourth Proportional to 172.87, 259.36 and 81.56

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Solution

The fourth proportional to 172.87, 259.36 and 81.56 is: 122.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    172.87 : 259.36 = 81.56 : x
  2. Step 2: Convert to fraction form
    172.87/259.36 = 81.56/x
  3. Step 3: Cross multiply
    172.87x = 259.36 × 81.56
  4. Step 4: Simplify right side
    172.87x = 21,152.96
  5. Step 5: Solve for x
    x = 21,152.96/172.87
  6. Step 6: Final answer
    x = 122.36

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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.