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Finding the Fourth Proportional to 66.89, 100.34 and 18.80

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Solution

The fourth proportional to 66.89, 100.34 and 18.80 is: 28.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.89 : 100.34 = 18.80 : x
  2. Step 2: Convert to fraction form
    66.89/100.34 = 18.80/x
  3. Step 3: Cross multiply
    66.89x = 100.34 × 18.80
  4. Step 4: Simplify right side
    66.89x = 1,886.24
  5. Step 5: Solve for x
    x = 1,886.24/66.89
  6. Step 6: Final answer
    x = 28.20

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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.