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Finding the Fourth Proportional to 66.81, 99.85 and 51.43

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Solution

The fourth proportional to 66.81, 99.85 and 51.43 is: 76.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.81 : 99.85 = 51.43 : x
  2. Step 2: Convert to fraction form
    66.81/99.85 = 51.43/x
  3. Step 3: Cross multiply
    66.81x = 99.85 × 51.43
  4. Step 4: Simplify right side
    66.81x = 5,135.29
  5. Step 5: Solve for x
    x = 5,135.29/66.81
  6. Step 6: Final answer
    x = 76.86

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.