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Finding the Fourth Proportional to 35.40, 48.85 and 20.85

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Solution

The fourth proportional to 35.40, 48.85 and 20.85 is: 28.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    35.40 : 48.85 = 20.85 : x
  2. Step 2: Convert to fraction form
    35.40/48.85 = 20.85/x
  3. Step 3: Cross multiply
    35.40x = 48.85 × 20.85
  4. Step 4: Simplify right side
    35.40x = 1,018.52
  5. Step 5: Solve for x
    x = 1,018.52/35.40
  6. Step 6: Final answer
    x = 28.77

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.