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Finding the Fourth Proportional to 90.83, 135.66 and 78.02

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Solution

The fourth proportional to 90.83, 135.66 and 78.02 is: 116.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.83 : 135.66 = 78.02 : x
  2. Step 2: Convert to fraction form
    90.83/135.66 = 78.02/x
  3. Step 3: Cross multiply
    90.83x = 135.66 × 78.02
  4. Step 4: Simplify right side
    90.83x = 10,584.53
  5. Step 5: Solve for x
    x = 10,584.53/90.83
  6. Step 6: Final answer
    x = 116.54

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.