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Finding the Fourth Proportional to 64.51, 96.78 and 21.18

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Solution

The fourth proportional to 64.51, 96.78 and 21.18 is: 31.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    64.51 : 96.78 = 21.18 : x
  2. Step 2: Convert to fraction form
    64.51/96.78 = 21.18/x
  3. Step 3: Cross multiply
    64.51x = 96.78 × 21.18
  4. Step 4: Simplify right side
    64.51x = 2,049.85
  5. Step 5: Solve for x
    x = 2,049.85/64.51
  6. Step 6: Final answer
    x = 31.78

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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.