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Finding the Fourth Proportional to 109.90, 163.99 and 91.90

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Solution

The fourth proportional to 109.90, 163.99 and 91.90 is: 137.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    109.90 : 163.99 = 91.90 : x
  2. Step 2: Convert to fraction form
    109.90/163.99 = 91.90/x
  3. Step 3: Cross multiply
    109.90x = 163.99 × 91.90
  4. Step 4: Simplify right side
    109.90x = 15,070.68
  5. Step 5: Solve for x
    x = 15,070.68/109.90
  6. Step 6: Final answer
    x = 137.13

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.