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Finding the Fourth Proportional to 91.79, 126.70 and 56.81

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Solution

The fourth proportional to 91.79, 126.70 and 56.81 is: 78.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.79 : 126.70 = 56.81 : x
  2. Step 2: Convert to fraction form
    91.79/126.70 = 56.81/x
  3. Step 3: Cross multiply
    91.79x = 126.70 × 56.81
  4. Step 4: Simplify right side
    91.79x = 7,198.56
  5. Step 5: Solve for x
    x = 7,198.56/91.79
  6. Step 6: Final answer
    x = 78.43

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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.