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Finding the Fourth Proportional to 115.42, 172.87 and 72.09

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Solution

The fourth proportional to 115.42, 172.87 and 72.09 is: 107.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    115.42 : 172.87 = 72.09 : x
  2. Step 2: Convert to fraction form
    115.42/172.87 = 72.09/x
  3. Step 3: Cross multiply
    115.42x = 172.87 × 72.09
  4. Step 4: Simplify right side
    115.42x = 12,462.02
  5. Step 5: Solve for x
    x = 12,462.02/115.42
  6. Step 6: Final answer
    x = 107.97

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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.