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Finding the Fourth Proportional to 90.85, 137 and 89.63

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Solution

The fourth proportional to 90.85, 137 and 89.63 is: 135.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.85 : 137 = 89.63 : x
  2. Step 2: Convert to fraction form
    90.85/137 = 89.63/x
  3. Step 3: Cross multiply
    90.85x = 137 × 89.63
  4. Step 4: Simplify right side
    90.85x = 12,279.31
  5. Step 5: Solve for x
    x = 12,279.31/90.85
  6. Step 6: Final answer
    x = 135.16

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.