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Finding the Fourth Proportional to 142.80, 213.92 and 70.72

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Solution

The fourth proportional to 142.80, 213.92 and 70.72 is: 105.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.80 : 213.92 = 70.72 : x
  2. Step 2: Convert to fraction form
    142.80/213.92 = 70.72/x
  3. Step 3: Cross multiply
    142.80x = 213.92 × 70.72
  4. Step 4: Simplify right side
    142.80x = 15,128.42
  5. Step 5: Solve for x
    x = 15,128.42/142.80
  6. Step 6: Final answer
    x = 105.94

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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.