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Finding the Fourth Proportional to 90.50, 135.78 and 65.81

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Solution

The fourth proportional to 90.50, 135.78 and 65.81 is: 98.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.50 : 135.78 = 65.81 : x
  2. Step 2: Convert to fraction form
    90.50/135.78 = 65.81/x
  3. Step 3: Cross multiply
    90.50x = 135.78 × 65.81
  4. Step 4: Simplify right side
    90.50x = 8,936.02
  5. Step 5: Solve for x
    x = 8,936.02/90.50
  6. Step 6: Final answer
    x = 98.74

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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.