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Finding the Fourth Proportional to 38.70, 53.18 and 31.42

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Solution

The fourth proportional to 38.70, 53.18 and 31.42 is: 43.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    38.70 : 53.18 = 31.42 : x
  2. Step 2: Convert to fraction form
    38.70/53.18 = 31.42/x
  3. Step 3: Cross multiply
    38.70x = 53.18 × 31.42
  4. Step 4: Simplify right side
    38.70x = 1,670.92
  5. Step 5: Solve for x
    x = 1,670.92/38.70
  6. Step 6: Final answer
    x = 43.18

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.