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Finding the Fourth Proportional to 90, 135.61 and 80.18

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Solution

The fourth proportional to 90, 135.61 and 80.18 is: 120.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    90 : 135.61 = 80.18 : x
  2. Step 2: Convert to fraction form
    90/135.61 = 80.18/x
  3. Step 3: Cross multiply
    90x = 135.61 × 80.18
  4. Step 4: Simplify right side
    90x = 10,873.21
  5. Step 5: Solve for x
    x = 10,873.21/90
  6. Step 6: Final answer
    x = 120.81

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1.5x scale

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.