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Finding the Fourth Proportional to 39.04, 53.87 and 21.79

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Solution

The fourth proportional to 39.04, 53.87 and 21.79 is: 30.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    39.04 : 53.87 = 21.79 : x
  2. Step 2: Convert to fraction form
    39.04/53.87 = 21.79/x
  3. Step 3: Cross multiply
    39.04x = 53.87 × 21.79
  4. Step 4: Simplify right side
    39.04x = 1,173.45
  5. Step 5: Solve for x
    x = 1,173.45/39.04
  6. Step 6: Final answer
    x = 30.06

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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.