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Finding the Fourth Proportional to 142.19, 213.29 and 90.87

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Solution

The fourth proportional to 142.19, 213.29 and 90.87 is: 136.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.19 : 213.29 = 90.87 : x
  2. Step 2: Convert to fraction form
    142.19/213.29 = 90.87/x
  3. Step 3: Cross multiply
    142.19x = 213.29 × 90.87
  4. Step 4: Simplify right side
    142.19x = 19,380.60
  5. Step 5: Solve for x
    x = 19,380.60/142.19
  6. Step 6: Final answer
    x = 136.31

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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.