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Finding the Fourth Proportional to 89.91, 135.07 and 78.57

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Solution

The fourth proportional to 89.91, 135.07 and 78.57 is: 118.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    89.91 : 135.07 = 78.57 : x
  2. Step 2: Convert to fraction form
    89.91/135.07 = 78.57/x
  3. Step 3: Cross multiply
    89.91x = 135.07 × 78.57
  4. Step 4: Simplify right side
    89.91x = 10,612.25
  5. Step 5: Solve for x
    x = 10,612.25/89.91
  6. Step 6: Final answer
    x = 118.03

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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.