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Finding the Fourth Proportional to 90.75, 135.38 and 87.59

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Solution

The fourth proportional to 90.75, 135.38 and 87.59 is: 130.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.75 : 135.38 = 87.59 : x
  2. Step 2: Convert to fraction form
    90.75/135.38 = 87.59/x
  3. Step 3: Cross multiply
    90.75x = 135.38 × 87.59
  4. Step 4: Simplify right side
    90.75x = 11,857.93
  5. Step 5: Solve for x
    x = 11,857.93/90.75
  6. Step 6: Final answer
    x = 130.67

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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.