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Finding the Fourth Proportional to 90.38, 135.80 and 81.95

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Solution

The fourth proportional to 90.38, 135.80 and 81.95 is: 123.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.38 : 135.80 = 81.95 : x
  2. Step 2: Convert to fraction form
    90.38/135.80 = 81.95/x
  3. Step 3: Cross multiply
    90.38x = 135.80 × 81.95
  4. Step 4: Simplify right side
    90.38x = 11,128.81
  5. Step 5: Solve for x
    x = 11,128.81/90.38
  6. Step 6: Final answer
    x = 123.13

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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.