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Finding the Fourth Proportional to 91.83, 126.78 and 72.12

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Solution

The fourth proportional to 91.83, 126.78 and 72.12 is: 99.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.83 : 126.78 = 72.12 : x
  2. Step 2: Convert to fraction form
    91.83/126.78 = 72.12/x
  3. Step 3: Cross multiply
    91.83x = 126.78 × 72.12
  4. Step 4: Simplify right side
    91.83x = 9,143.37
  5. Step 5: Solve for x
    x = 9,143.37/91.83
  6. Step 6: Final answer
    x = 99.57

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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.