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Finding the Fourth Proportional to 90.36, 134.81 and 78.93

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Solution

The fourth proportional to 90.36, 134.81 and 78.93 is: 117.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.36 : 134.81 = 78.93 : x
  2. Step 2: Convert to fraction form
    90.36/134.81 = 78.93/x
  3. Step 3: Cross multiply
    90.36x = 134.81 × 78.93
  4. Step 4: Simplify right side
    90.36x = 10,640.75
  5. Step 5: Solve for x
    x = 10,640.75/90.36
  6. Step 6: Final answer
    x = 117.76

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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.