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Finding the Fourth Proportional to 120.21, 180.32 and 66.45

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Solution

The fourth proportional to 120.21, 180.32 and 66.45 is: 99.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.21 : 180.32 = 66.45 : x
  2. Step 2: Convert to fraction form
    120.21/180.32 = 66.45/x
  3. Step 3: Cross multiply
    120.21x = 180.32 × 66.45
  4. Step 4: Simplify right side
    120.21x = 11,982.26
  5. Step 5: Solve for x
    x = 11,982.26/120.21
  6. Step 6: Final answer
    x = 99.68

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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.