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Finding the Fourth Proportional to 91.28, 137.52 and 79.81

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Solution

The fourth proportional to 91.28, 137.52 and 79.81 is: 120.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.28 : 137.52 = 79.81 : x
  2. Step 2: Convert to fraction form
    91.28/137.52 = 79.81/x
  3. Step 3: Cross multiply
    91.28x = 137.52 × 79.81
  4. Step 4: Simplify right side
    91.28x = 10,975.74
  5. Step 5: Solve for x
    x = 10,975.74/91.28
  6. Step 6: Final answer
    x = 120.25

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.