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Finding the Fourth Proportional to 115.12, 172.41 and 87.85

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Solution

The fourth proportional to 115.12, 172.41 and 87.85 is: 131.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    115.12 : 172.41 = 87.85 : x
  2. Step 2: Convert to fraction form
    115.12/172.41 = 87.85/x
  3. Step 3: Cross multiply
    115.12x = 172.41 × 87.85
  4. Step 4: Simplify right side
    115.12x = 15,146.22
  5. Step 5: Solve for x
    x = 15,146.22/115.12
  6. Step 6: Final answer
    x = 131.57

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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.