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Finding the Fourth Proportional to 141.72, 212.40 and 80.91

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Solution

The fourth proportional to 141.72, 212.40 and 80.91 is: 121.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    141.72 : 212.40 = 80.91 : x
  2. Step 2: Convert to fraction form
    141.72/212.40 = 80.91/x
  3. Step 3: Cross multiply
    141.72x = 212.40 × 80.91
  4. Step 4: Simplify right side
    141.72x = 17,185.28
  5. Step 5: Solve for x
    x = 17,185.28/141.72
  6. Step 6: Final answer
    x = 121.26

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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.