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Finding the Fourth Proportional to 52.80, 78.60 and 52.21

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Solution

The fourth proportional to 52.80, 78.60 and 52.21 is: 77.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    52.80 : 78.60 = 52.21 : x
  2. Step 2: Convert to fraction form
    52.80/78.60 = 52.21/x
  3. Step 3: Cross multiply
    52.80x = 78.60 × 52.21
  4. Step 4: Simplify right side
    52.80x = 4,103.71
  5. Step 5: Solve for x
    x = 4,103.71/52.80
  6. Step 6: Final answer
    x = 77.73

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.