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Finding the Fourth Proportional to 31.64, 47.72 and 31.20

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Solution

The fourth proportional to 31.64, 47.72 and 31.20 is: 47.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.64 : 47.72 = 31.20 : x
  2. Step 2: Convert to fraction form
    31.64/47.72 = 31.20/x
  3. Step 3: Cross multiply
    31.64x = 47.72 × 31.20
  4. Step 4: Simplify right side
    31.64x = 1,488.86
  5. Step 5: Solve for x
    x = 1,488.86/31.64
  6. Step 6: Final answer
    x = 47.06

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.