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Finding the Fourth Proportional to 2.78, 4.18 and 2.18

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Solution

The fourth proportional to 2.78, 4.18 and 2.18 is: 3.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    2.78 : 4.18 = 2.18 : x
  2. Step 2: Convert to fraction form
    2.78/4.18 = 2.18/x
  3. Step 3: Cross multiply
    2.78x = 4.18 × 2.18
  4. Step 4: Simplify right side
    2.78x = 9.11
  5. Step 5: Solve for x
    x = 9.11/2.78
  6. Step 6: Final answer
    x = 3.28

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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.