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Finding the Fourth Proportional to 142, 212.78 and 77.92

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Solution

The fourth proportional to 142, 212.78 and 77.92 is: 116.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    142 : 212.78 = 77.92 : x
  2. Step 2: Convert to fraction form
    142/212.78 = 77.92/x
  3. Step 3: Cross multiply
    142x = 212.78 × 77.92
  4. Step 4: Simplify right side
    142x = 16,579.82
  5. Step 5: Solve for x
    x = 16,579.82/142
  6. Step 6: Final answer
    x = 116.76

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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.