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Finding the Fourth Proportional to 38.90, 53.61 and 30.71

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Solution

The fourth proportional to 38.90, 53.61 and 30.71 is: 42.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    38.90 : 53.61 = 30.71 : x
  2. Step 2: Convert to fraction form
    38.90/53.61 = 30.71/x
  3. Step 3: Cross multiply
    38.90x = 53.61 × 30.71
  4. Step 4: Simplify right side
    38.90x = 1,646.36
  5. Step 5: Solve for x
    x = 1,646.36/38.90
  6. Step 6: Final answer
    x = 42.32

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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.