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Finding the Fourth Proportional to 51.84, 77.76 and 21.40

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Solution

The fourth proportional to 51.84, 77.76 and 21.40 is: 32.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    51.84 : 77.76 = 21.40 : x
  2. Step 2: Convert to fraction form
    51.84/77.76 = 21.40/x
  3. Step 3: Cross multiply
    51.84x = 77.76 × 21.40
  4. Step 4: Simplify right side
    51.84x = 1,664.06
  5. Step 5: Solve for x
    x = 1,664.06/51.84
  6. Step 6: Final answer
    x = 32.10

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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.