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Finding the Fourth Proportional to 47.20, 70.78 and 21.51

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Solution

The fourth proportional to 47.20, 70.78 and 21.51 is: 32.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    47.20 : 70.78 = 21.51 : x
  2. Step 2: Convert to fraction form
    47.20/70.78 = 21.51/x
  3. Step 3: Cross multiply
    47.20x = 70.78 × 21.51
  4. Step 4: Simplify right side
    47.20x = 1,522.48
  5. Step 5: Solve for x
    x = 1,522.48/47.20
  6. Step 6: Final answer
    x = 32.26

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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.