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Finding the Fourth Proportional to 91.08, 136.35 and 72.90

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Solution

The fourth proportional to 91.08, 136.35 and 72.90 is: 109.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.08 : 136.35 = 72.90 : x
  2. Step 2: Convert to fraction form
    91.08/136.35 = 72.90/x
  3. Step 3: Cross multiply
    91.08x = 136.35 × 72.90
  4. Step 4: Simplify right side
    91.08x = 9,939.92
  5. Step 5: Solve for x
    x = 9,939.92/91.08
  6. Step 6: Final answer
    x = 109.13

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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.