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Finding the Fourth Proportional to 91.15, 125.80 and 87.05

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Solution

The fourth proportional to 91.15, 125.80 and 87.05 is: 120.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.15 : 125.80 = 87.05 : x
  2. Step 2: Convert to fraction form
    91.15/125.80 = 87.05/x
  3. Step 3: Cross multiply
    91.15x = 125.80 × 87.05
  4. Step 4: Simplify right side
    91.15x = 10,951.12
  5. Step 5: Solve for x
    x = 10,951.12/91.15
  6. Step 6: Final answer
    x = 120.14

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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.