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Finding the Fourth Proportional to 106.80, 159.38 and 90.80

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Solution

The fourth proportional to 106.80, 159.38 and 90.80 is: 135.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    106.80 : 159.38 = 90.80 : x
  2. Step 2: Convert to fraction form
    106.80/159.38 = 90.80/x
  3. Step 3: Cross multiply
    106.80x = 159.38 × 90.80
  4. Step 4: Simplify right side
    106.80x = 14,471.70
  5. Step 5: Solve for x
    x = 14,471.70/106.80
  6. Step 6: Final answer
    x = 135.50

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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.