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Finding the Fourth Proportional to 142.72, 213.63 and 91.29

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Solution

The fourth proportional to 142.72, 213.63 and 91.29 is: 136.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.72 : 213.63 = 91.29 : x
  2. Step 2: Convert to fraction form
    142.72/213.63 = 91.29/x
  3. Step 3: Cross multiply
    142.72x = 213.63 × 91.29
  4. Step 4: Simplify right side
    142.72x = 19,502.28
  5. Step 5: Solve for x
    x = 19,502.28/142.72
  6. Step 6: Final answer
    x = 136.65

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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.