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Finding the Fourth Proportional to 90.86, 136.08 and 71.48

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Solution

The fourth proportional to 90.86, 136.08 and 71.48 is: 107.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.86 : 136.08 = 71.48 : x
  2. Step 2: Convert to fraction form
    90.86/136.08 = 71.48/x
  3. Step 3: Cross multiply
    90.86x = 136.08 × 71.48
  4. Step 4: Simplify right side
    90.86x = 9,727.34
  5. Step 5: Solve for x
    x = 9,727.34/90.86
  6. Step 6: Final answer
    x = 107.06

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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.