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Finding the Fourth Proportional to 142.40, 213.07 and 87.35

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Solution

The fourth proportional to 142.40, 213.07 and 87.35 is: 130.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.40 : 213.07 = 87.35 : x
  2. Step 2: Convert to fraction form
    142.40/213.07 = 87.35/x
  3. Step 3: Cross multiply
    142.40x = 213.07 × 87.35
  4. Step 4: Simplify right side
    142.40x = 18,611.66
  5. Step 5: Solve for x
    x = 18,611.66/142.40
  6. Step 6: Final answer
    x = 130.70

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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.