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Finding the Fourth Proportional to 2.90, 4 and 2.80

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Solution

The fourth proportional to 2.90, 4 and 2.80 is: 3.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    2.90 : 4 = 2.80 : x
  2. Step 2: Convert to fraction form
    2.90/4 = 2.80/x
  3. Step 3: Cross multiply
    2.90x = 4 × 2.80
  4. Step 4: Simplify right side
    2.90x = 11.20
  5. Step 5: Solve for x
    x = 11.20/2.90
  6. Step 6: Final answer
    x = 3.86

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.