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Finding the Fourth Proportional to 47.10, 64.80 and 39.72

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Solution

The fourth proportional to 47.10, 64.80 and 39.72 is: 54.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    47.10 : 64.80 = 39.72 : x
  2. Step 2: Convert to fraction form
    47.10/64.80 = 39.72/x
  3. Step 3: Cross multiply
    47.10x = 64.80 × 39.72
  4. Step 4: Simplify right side
    47.10x = 2,573.86
  5. Step 5: Solve for x
    x = 2,573.86/47.10
  6. Step 6: Final answer
    x = 54.65

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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.