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Finding the Fourth Proportional to 115.39, 172.83 and 90.85

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Solution

The fourth proportional to 115.39, 172.83 and 90.85 is: 136.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    115.39 : 172.83 = 90.85 : x
  2. Step 2: Convert to fraction form
    115.39/172.83 = 90.85/x
  3. Step 3: Cross multiply
    115.39x = 172.83 × 90.85
  4. Step 4: Simplify right side
    115.39x = 15,701.51
  5. Step 5: Solve for x
    x = 15,701.51/115.39
  6. Step 6: Final answer
    x = 136.07

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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.