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Finding the Fourth Proportional to 38.78, 53.59 and 31.86

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Solution

The fourth proportional to 38.78, 53.59 and 31.86 is: 44.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    38.78 : 53.59 = 31.86 : x
  2. Step 2: Convert to fraction form
    38.78/53.59 = 31.86/x
  3. Step 3: Cross multiply
    38.78x = 53.59 × 31.86
  4. Step 4: Simplify right side
    38.78x = 1,707.58
  5. Step 5: Solve for x
    x = 1,707.58/38.78
  6. Step 6: Final answer
    x = 44.03

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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.