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Finding the Fourth Proportional to 90.72, 135.33 and 89.28

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Solution

The fourth proportional to 90.72, 135.33 and 89.28 is: 133.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.72 : 135.33 = 89.28 : x
  2. Step 2: Convert to fraction form
    90.72/135.33 = 89.28/x
  3. Step 3: Cross multiply
    90.72x = 135.33 × 89.28
  4. Step 4: Simplify right side
    90.72x = 12,082.26
  5. Step 5: Solve for x
    x = 12,082.26/90.72
  6. Step 6: Final answer
    x = 133.18

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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.