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Finding the Fourth Proportional to 90.45, 135.81 and 74.25

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Solution

The fourth proportional to 90.45, 135.81 and 74.25 is: 111.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.45 : 135.81 = 74.25 : x
  2. Step 2: Convert to fraction form
    90.45/135.81 = 74.25/x
  3. Step 3: Cross multiply
    90.45x = 135.81 × 74.25
  4. Step 4: Simplify right side
    90.45x = 10,083.89
  5. Step 5: Solve for x
    x = 10,083.89/90.45
  6. Step 6: Final answer
    x = 111.49

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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.