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Finding the Fourth Proportional to 45.15, 67.40 and 39.75

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Solution

The fourth proportional to 45.15, 67.40 and 39.75 is: 59.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    45.15 : 67.40 = 39.75 : x
  2. Step 2: Convert to fraction form
    45.15/67.40 = 39.75/x
  3. Step 3: Cross multiply
    45.15x = 67.40 × 39.75
  4. Step 4: Simplify right side
    45.15x = 2,679.15
  5. Step 5: Solve for x
    x = 2,679.15/45.15
  6. Step 6: Final answer
    x = 59.34

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.