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Finding the Fourth Proportional to 66.43, 99.65 and 20.76

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Solution

The fourth proportional to 66.43, 99.65 and 20.76 is: 31.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.43 : 99.65 = 20.76 : x
  2. Step 2: Convert to fraction form
    66.43/99.65 = 20.76/x
  3. Step 3: Cross multiply
    66.43x = 99.65 × 20.76
  4. Step 4: Simplify right side
    66.43x = 2,069.08
  5. Step 5: Solve for x
    x = 2,069.08/66.43
  6. Step 6: Final answer
    x = 31.15

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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.