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Finding the Fourth Proportional to 91.75, 126.32 and 79.40

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Solution

The fourth proportional to 91.75, 126.32 and 79.40 is: 109.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.75 : 126.32 = 79.40 : x
  2. Step 2: Convert to fraction form
    91.75/126.32 = 79.40/x
  3. Step 3: Cross multiply
    91.75x = 126.32 × 79.40
  4. Step 4: Simplify right side
    91.75x = 10,029.81
  5. Step 5: Solve for x
    x = 10,029.81/91.75
  6. Step 6: Final answer
    x = 109.32

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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.