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Finding the Fourth Proportional to 125.12, 172.44 and 85.70

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Solution

The fourth proportional to 125.12, 172.44 and 85.70 is: 118.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    125.12 : 172.44 = 85.70 : x
  2. Step 2: Convert to fraction form
    125.12/172.44 = 85.70/x
  3. Step 3: Cross multiply
    125.12x = 172.44 × 85.70
  4. Step 4: Simplify right side
    125.12x = 14,778.54
  5. Step 5: Solve for x
    x = 14,778.54/125.12
  6. Step 6: Final answer
    x = 118.11

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.