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Finding the Fourth Proportional to 66.81, 92.21 and 39.19

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Solution

The fourth proportional to 66.81, 92.21 and 39.19 is: 54.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.81 : 92.21 = 39.19 : x
  2. Step 2: Convert to fraction form
    66.81/92.21 = 39.19/x
  3. Step 3: Cross multiply
    66.81x = 92.21 × 39.19
  4. Step 4: Simplify right side
    66.81x = 3,613.71
  5. Step 5: Solve for x
    x = 3,613.71/66.81
  6. Step 6: Final answer
    x = 54.09

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.