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Finding the Fourth Proportional to 30.99, 42.78 and 20.07

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Solution

The fourth proportional to 30.99, 42.78 and 20.07 is: 27.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.99 : 42.78 = 20.07 : x
  2. Step 2: Convert to fraction form
    30.99/42.78 = 20.07/x
  3. Step 3: Cross multiply
    30.99x = 42.78 × 20.07
  4. Step 4: Simplify right side
    30.99x = 858.59
  5. Step 5: Solve for x
    x = 858.59/30.99
  6. Step 6: Final answer
    x = 27.71

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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.