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Finding the Fourth Proportional to 52.40, 78.62 and 19.90

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Solution

The fourth proportional to 52.40, 78.62 and 19.90 is: 29.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    52.40 : 78.62 = 19.90 : x
  2. Step 2: Convert to fraction form
    52.40/78.62 = 19.90/x
  3. Step 3: Cross multiply
    52.40x = 78.62 × 19.90
  4. Step 4: Simplify right side
    52.40x = 1,564.54
  5. Step 5: Solve for x
    x = 1,564.54/52.40
  6. Step 6: Final answer
    x = 29.86

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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.