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Finding the Fourth Proportional to 89.15, 134.29 and 87.40

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Solution

The fourth proportional to 89.15, 134.29 and 87.40 is: 131.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    89.15 : 134.29 = 87.40 : x
  2. Step 2: Convert to fraction form
    89.15/134.29 = 87.40/x
  3. Step 3: Cross multiply
    89.15x = 134.29 × 87.40
  4. Step 4: Simplify right side
    89.15x = 11,736.95
  5. Step 5: Solve for x
    x = 11,736.95/89.15
  6. Step 6: Final answer
    x = 131.65

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.