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Finding the Fourth Proportional to 90.30, 135.57 and 76.74

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Solution

The fourth proportional to 90.30, 135.57 and 76.74 is: 115.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.30 : 135.57 = 76.74 : x
  2. Step 2: Convert to fraction form
    90.30/135.57 = 76.74/x
  3. Step 3: Cross multiply
    90.30x = 135.57 × 76.74
  4. Step 4: Simplify right side
    90.30x = 10,403.64
  5. Step 5: Solve for x
    x = 10,403.64/90.30
  6. Step 6: Final answer
    x = 115.21

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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.