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Finding the Fourth Proportional to 112.92, 155.70 and 90.78

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Solution

The fourth proportional to 112.92, 155.70 and 90.78 is: 125.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    112.92 : 155.70 = 90.78 : x
  2. Step 2: Convert to fraction form
    112.92/155.70 = 90.78/x
  3. Step 3: Cross multiply
    112.92x = 155.70 × 90.78
  4. Step 4: Simplify right side
    112.92x = 14,134.45
  5. Step 5: Solve for x
    x = 14,134.45/112.92
  6. Step 6: Final answer
    x = 125.17

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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.