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Finding the Fourth Proportional to 64.80, 97.21 and 21.47

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Solution

The fourth proportional to 64.80, 97.21 and 21.47 is: 32.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    64.80 : 97.21 = 21.47 : x
  2. Step 2: Convert to fraction form
    64.80/97.21 = 21.47/x
  3. Step 3: Cross multiply
    64.80x = 97.21 × 21.47
  4. Step 4: Simplify right side
    64.80x = 2,086.86
  5. Step 5: Solve for x
    x = 2,086.86/64.80
  6. Step 6: Final answer
    x = 32.21

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.