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Finding the Fourth Proportional to 66.90, 100.35 and 30.81

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Solution

The fourth proportional to 66.90, 100.35 and 30.81 is: 46.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.90 : 100.35 = 30.81 : x
  2. Step 2: Convert to fraction form
    66.90/100.35 = 30.81/x
  3. Step 3: Cross multiply
    66.90x = 100.35 × 30.81
  4. Step 4: Simplify right side
    66.90x = 3,091.78
  5. Step 5: Solve for x
    x = 3,091.78/66.90
  6. Step 6: Final answer
    x = 46.22

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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.