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Finding the Fourth Proportional to 90.81, 125.28 and 55.84

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Solution

The fourth proportional to 90.81, 125.28 and 55.84 is: 77.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.81 : 125.28 = 55.84 : x
  2. Step 2: Convert to fraction form
    90.81/125.28 = 55.84/x
  3. Step 3: Cross multiply
    90.81x = 125.28 × 55.84
  4. Step 4: Simplify right side
    90.81x = 6,995.64
  5. Step 5: Solve for x
    x = 6,995.64/90.81
  6. Step 6: Final answer
    x = 77.04

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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.