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Finding the Fourth Proportional to 91.21, 136.80 and 30.38

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Solution

The fourth proportional to 91.21, 136.80 and 30.38 is: 45.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.21 : 136.80 = 30.38 : x
  2. Step 2: Convert to fraction form
    91.21/136.80 = 30.38/x
  3. Step 3: Cross multiply
    91.21x = 136.80 × 30.38
  4. Step 4: Simplify right side
    91.21x = 4,155.98
  5. Step 5: Solve for x
    x = 4,155.98/91.21
  6. Step 6: Final answer
    x = 45.57

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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.