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Finding the Fourth Proportional to 90.09, 134.84 and 78.21

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Solution

The fourth proportional to 90.09, 134.84 and 78.21 is: 117.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.09 : 134.84 = 78.21 : x
  2. Step 2: Convert to fraction form
    90.09/134.84 = 78.21/x
  3. Step 3: Cross multiply
    90.09x = 134.84 × 78.21
  4. Step 4: Simplify right side
    90.09x = 10,545.45
  5. Step 5: Solve for x
    x = 10,545.45/90.09
  6. Step 6: Final answer
    x = 117.05

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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.