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Finding the Fourth Proportional to 75.40, 113.18 and 66.90

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Solution

The fourth proportional to 75.40, 113.18 and 66.90 is: 100.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    75.40 : 113.18 = 66.90 : x
  2. Step 2: Convert to fraction form
    75.40/113.18 = 66.90/x
  3. Step 3: Cross multiply
    75.40x = 113.18 × 66.90
  4. Step 4: Simplify right side
    75.40x = 7,571.74
  5. Step 5: Solve for x
    x = 7,571.74/75.40
  6. Step 6: Final answer
    x = 100.42

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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.