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Finding the Fourth Proportional to 125.28, 172.90 and 83.91

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Solution

The fourth proportional to 125.28, 172.90 and 83.91 is: 115.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    125.28 : 172.90 = 83.91 : x
  2. Step 2: Convert to fraction form
    125.28/172.90 = 83.91/x
  3. Step 3: Cross multiply
    125.28x = 172.90 × 83.91
  4. Step 4: Simplify right side
    125.28x = 14,508.04
  5. Step 5: Solve for x
    x = 14,508.04/125.28
  6. Step 6: Final answer
    x = 115.80

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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.