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Finding the Fourth Proportional to 1.39, 2.07 and 1.20

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Solution

The fourth proportional to 1.39, 2.07 and 1.20 is: 1.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    1.39 : 2.07 = 1.20 : x
  2. Step 2: Convert to fraction form
    1.39/2.07 = 1.20/x
  3. Step 3: Cross multiply
    1.39x = 2.07 × 1.20
  4. Step 4: Simplify right side
    1.39x = 2.47
  5. Step 5: Solve for x
    x = 2.47/1.39
  6. Step 6: Final answer
    x = 1.78

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.