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Finding the Fourth Proportional to 66.40, 99.66 and 51.28

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Solution

The fourth proportional to 66.40, 99.66 and 51.28 is: 76.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.40 : 99.66 = 51.28 : x
  2. Step 2: Convert to fraction form
    66.40/99.66 = 51.28/x
  3. Step 3: Cross multiply
    66.40x = 99.66 × 51.28
  4. Step 4: Simplify right side
    66.40x = 5,110.56
  5. Step 5: Solve for x
    x = 5,110.56/66.40
  6. Step 6: Final answer
    x = 76.97

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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.