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Finding the Fourth Proportional to 30.77, 42.47 and 19.85

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Solution

The fourth proportional to 30.77, 42.47 and 19.85 is: 27.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.77 : 42.47 = 19.85 : x
  2. Step 2: Convert to fraction form
    30.77/42.47 = 19.85/x
  3. Step 3: Cross multiply
    30.77x = 42.47 × 19.85
  4. Step 4: Simplify right side
    30.77x = 843.03
  5. Step 5: Solve for x
    x = 843.03/30.77
  6. Step 6: Final answer
    x = 27.40

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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.