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Finding the Fourth Proportional to 2.61, 3.91 and 0.91

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Solution

The fourth proportional to 2.61, 3.91 and 0.91 is: 1.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    2.61 : 3.91 = 0.91 : x
  2. Step 2: Convert to fraction form
    2.61/3.91 = 0.91/x
  3. Step 3: Cross multiply
    2.61x = 3.91 × 0.91
  4. Step 4: Simplify right side
    2.61x = 3.57
  5. Step 5: Solve for x
    x = 3.57/2.61
  6. Step 6: Final answer
    x = 1.37

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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.