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Finding the Fourth Proportional to 142.69, 213.90 and 77.65

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Solution

The fourth proportional to 142.69, 213.90 and 77.65 is: 116.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.69 : 213.90 = 77.65 : x
  2. Step 2: Convert to fraction form
    142.69/213.90 = 77.65/x
  3. Step 3: Cross multiply
    142.69x = 213.90 × 77.65
  4. Step 4: Simplify right side
    142.69x = 16,609.34
  5. Step 5: Solve for x
    x = 16,609.34/142.69
  6. Step 6: Final answer
    x = 116.40

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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.