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Finding the Fourth Proportional to 75.90, 113.70 and 39.75

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Solution

The fourth proportional to 75.90, 113.70 and 39.75 is: 59.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    75.90 : 113.70 = 39.75 : x
  2. Step 2: Convert to fraction form
    75.90/113.70 = 39.75/x
  3. Step 3: Cross multiply
    75.90x = 113.70 × 39.75
  4. Step 4: Simplify right side
    75.90x = 4,519.58
  5. Step 5: Solve for x
    x = 4,519.58/75.90
  6. Step 6: Final answer
    x = 59.55

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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.