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Finding the Fourth Proportional to 51.64, 77.49 and 21.21

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Solution

The fourth proportional to 51.64, 77.49 and 21.21 is: 31.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    51.64 : 77.49 = 21.21 : x
  2. Step 2: Convert to fraction form
    51.64/77.49 = 21.21/x
  3. Step 3: Cross multiply
    51.64x = 77.49 × 21.21
  4. Step 4: Simplify right side
    51.64x = 1,643.71
  5. Step 5: Solve for x
    x = 1,643.71/51.64
  6. Step 6: Final answer
    x = 31.83

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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.