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Finding the Fourth Proportional to 31.79, 47.49 and 30.78

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Solution

The fourth proportional to 31.79, 47.49 and 30.78 is: 45.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.79 : 47.49 = 30.78 : x
  2. Step 2: Convert to fraction form
    31.79/47.49 = 30.78/x
  3. Step 3: Cross multiply
    31.79x = 47.49 × 30.78
  4. Step 4: Simplify right side
    31.79x = 1,461.63
  5. Step 5: Solve for x
    x = 1,461.63/31.79
  6. Step 6: Final answer
    x = 45.97

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.