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Finding the Fourth Proportional to 115.80, 173.78 and 90.20

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Solution

The fourth proportional to 115.80, 173.78 and 90.20 is: 135.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    115.80 : 173.78 = 90.20 : x
  2. Step 2: Convert to fraction form
    115.80/173.78 = 90.20/x
  3. Step 3: Cross multiply
    115.80x = 173.78 × 90.20
  4. Step 4: Simplify right side
    115.80x = 15,673.64
  5. Step 5: Solve for x
    x = 15,673.64/115.80
  6. Step 6: Final answer
    x = 135.35

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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.