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Finding the Fourth Proportional to 125.15, 172.67 and 80.90

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Solution

The fourth proportional to 125.15, 172.67 and 80.90 is: 111.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    125.15 : 172.67 = 80.90 : x
  2. Step 2: Convert to fraction form
    125.15/172.67 = 80.90/x
  3. Step 3: Cross multiply
    125.15x = 172.67 × 80.90
  4. Step 4: Simplify right side
    125.15x = 13,968.38
  5. Step 5: Solve for x
    x = 13,968.38/125.15
  6. Step 6: Final answer
    x = 111.62

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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.