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Finding the Fourth Proportional to 109.91, 165.09 and 87.05

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Solution

The fourth proportional to 109.91, 165.09 and 87.05 is: 130.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    109.91 : 165.09 = 87.05 : x
  2. Step 2: Convert to fraction form
    109.91/165.09 = 87.05/x
  3. Step 3: Cross multiply
    109.91x = 165.09 × 87.05
  4. Step 4: Simplify right side
    109.91x = 14,371.08
  5. Step 5: Solve for x
    x = 14,371.08/109.91
  6. Step 6: Final answer
    x = 130.75

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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.