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Finding the Fourth Proportional to 91.72, 126.51 and 81.19

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Solution

The fourth proportional to 91.72, 126.51 and 81.19 is: 111.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.72 : 126.51 = 81.19 : x
  2. Step 2: Convert to fraction form
    91.72/126.51 = 81.19/x
  3. Step 3: Cross multiply
    91.72x = 126.51 × 81.19
  4. Step 4: Simplify right side
    91.72x = 10,271.35
  5. Step 5: Solve for x
    x = 10,271.35/91.72
  6. Step 6: Final answer
    x = 111.99

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.