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Finding the Fourth Proportional to 38.77, 53.42 and 28.40

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Solution

The fourth proportional to 38.77, 53.42 and 28.40 is: 39.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    38.77 : 53.42 = 28.40 : x
  2. Step 2: Convert to fraction form
    38.77/53.42 = 28.40/x
  3. Step 3: Cross multiply
    38.77x = 53.42 × 28.40
  4. Step 4: Simplify right side
    38.77x = 1,516.72
  5. Step 5: Solve for x
    x = 1,516.72/38.77
  6. Step 6: Final answer
    x = 39.12

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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.