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Finding the Fourth Proportional to 91.40, 137.16 and 87.56

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Solution

The fourth proportional to 91.40, 137.16 and 87.56 is: 131.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.40 : 137.16 = 87.56 : x
  2. Step 2: Convert to fraction form
    91.40/137.16 = 87.56/x
  3. Step 3: Cross multiply
    91.40x = 137.16 × 87.56
  4. Step 4: Simplify right side
    91.40x = 12,009.73
  5. Step 5: Solve for x
    x = 12,009.73/91.40
  6. Step 6: Final answer
    x = 131.40

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.