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Finding the Fourth Proportional to 51.90, 77.90 and 21.49

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Solution

The fourth proportional to 51.90, 77.90 and 21.49 is: 32.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    51.90 : 77.90 = 21.49 : x
  2. Step 2: Convert to fraction form
    51.90/77.90 = 21.49/x
  3. Step 3: Cross multiply
    51.90x = 77.90 × 21.49
  4. Step 4: Simplify right side
    51.90x = 1,673.77
  5. Step 5: Solve for x
    x = 1,673.77/51.90
  6. Step 6: Final answer
    x = 32.25

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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.