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Finding the Fourth Proportional to 45.18, 67.68 and 21.15

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Solution

The fourth proportional to 45.18, 67.68 and 21.15 is: 31.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    45.18 : 67.68 = 21.15 : x
  2. Step 2: Convert to fraction form
    45.18/67.68 = 21.15/x
  3. Step 3: Cross multiply
    45.18x = 67.68 × 21.15
  4. Step 4: Simplify right side
    45.18x = 1,431.43
  5. Step 5: Solve for x
    x = 1,431.43/45.18
  6. Step 6: Final answer
    x = 31.68

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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.