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Finding the Fourth Proportional to 38.79, 53.55 and 31.50

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Solution

The fourth proportional to 38.79, 53.55 and 31.50 is: 43.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    38.79 : 53.55 = 31.50 : x
  2. Step 2: Convert to fraction form
    38.79/53.55 = 31.50/x
  3. Step 3: Cross multiply
    38.79x = 53.55 × 31.50
  4. Step 4: Simplify right side
    38.79x = 1,686.83
  5. Step 5: Solve for x
    x = 1,686.83/38.79
  6. Step 6: Final answer
    x = 43.49

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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.