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Finding the Fourth Proportional to 66.28, 99.42 and 18.20

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Solution

The fourth proportional to 66.28, 99.42 and 18.20 is: 27.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.28 : 99.42 = 18.20 : x
  2. Step 2: Convert to fraction form
    66.28/99.42 = 18.20/x
  3. Step 3: Cross multiply
    66.28x = 99.42 × 18.20
  4. Step 4: Simplify right side
    66.28x = 1,809.44
  5. Step 5: Solve for x
    x = 1,809.44/66.28
  6. Step 6: Final answer
    x = 27.30

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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.