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Finding the Fourth Proportional to 91.47, 126.36 and 77.81

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Solution

The fourth proportional to 91.47, 126.36 and 77.81 is: 107.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.47 : 126.36 = 77.81 : x
  2. Step 2: Convert to fraction form
    91.47/126.36 = 77.81/x
  3. Step 3: Cross multiply
    91.47x = 126.36 × 77.81
  4. Step 4: Simplify right side
    91.47x = 9,831.44
  5. Step 5: Solve for x
    x = 9,831.44/91.47
  6. Step 6: Final answer
    x = 107.48

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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.