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Finding the Fourth Proportional to 45.18, 67.79 and 20.79

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Solution

The fourth proportional to 45.18, 67.79 and 20.79 is: 31.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    45.18 : 67.79 = 20.79 : x
  2. Step 2: Convert to fraction form
    45.18/67.79 = 20.79/x
  3. Step 3: Cross multiply
    45.18x = 67.79 × 20.79
  4. Step 4: Simplify right side
    45.18x = 1,409.25
  5. Step 5: Solve for x
    x = 1,409.25/45.18
  6. Step 6: Final answer
    x = 31.19

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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.