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Finding the Fourth Proportional to 125.18, 172.80 and 86.42

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Solution

The fourth proportional to 125.18, 172.80 and 86.42 is: 119.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    125.18 : 172.80 = 86.42 : x
  2. Step 2: Convert to fraction form
    125.18/172.80 = 86.42/x
  3. Step 3: Cross multiply
    125.18x = 172.80 × 86.42
  4. Step 4: Simplify right side
    125.18x = 14,933.38
  5. Step 5: Solve for x
    x = 14,933.38/125.18
  6. Step 6: Final answer
    x = 119.30

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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.