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Finding the Fourth Proportional to 91.79, 126.63 and 72.12

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Solution

The fourth proportional to 91.79, 126.63 and 72.12 is: 99.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.79 : 126.63 = 72.12 : x
  2. Step 2: Convert to fraction form
    91.79/126.63 = 72.12/x
  3. Step 3: Cross multiply
    91.79x = 126.63 × 72.12
  4. Step 4: Simplify right side
    91.79x = 9,132.56
  5. Step 5: Solve for x
    x = 9,132.56/91.79
  6. Step 6: Final answer
    x = 99.50

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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.