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Finding the Fourth Proportional to 109.72, 165.22 and 90.64

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Solution

The fourth proportional to 109.72, 165.22 and 90.64 is: 136.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    109.72 : 165.22 = 90.64 : x
  2. Step 2: Convert to fraction form
    109.72/165.22 = 90.64/x
  3. Step 3: Cross multiply
    109.72x = 165.22 × 90.64
  4. Step 4: Simplify right side
    109.72x = 14,975.54
  5. Step 5: Solve for x
    x = 14,975.54/109.72
  6. Step 6: Final answer
    x = 136.49

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.