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Finding the Fourth Proportional to 142.45, 213.75 and 70.31

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Solution

The fourth proportional to 142.45, 213.75 and 70.31 is: 105.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.45 : 213.75 = 70.31 : x
  2. Step 2: Convert to fraction form
    142.45/213.75 = 70.31/x
  3. Step 3: Cross multiply
    142.45x = 213.75 × 70.31
  4. Step 4: Simplify right side
    142.45x = 15,029.30
  5. Step 5: Solve for x
    x = 15,029.30/142.45
  6. Step 6: Final answer
    x = 105.51

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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.