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Finding the Fourth Proportional to 126.66, 189.90 and 77.85

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Solution

The fourth proportional to 126.66, 189.90 and 77.85 is: 116.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    126.66 : 189.90 = 77.85 : x
  2. Step 2: Convert to fraction form
    126.66/189.90 = 77.85/x
  3. Step 3: Cross multiply
    126.66x = 189.90 × 77.85
  4. Step 4: Simplify right side
    126.66x = 14,783.72
  5. Step 5: Solve for x
    x = 14,783.72/126.66
  6. Step 6: Final answer
    x = 116.72

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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.