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Finding the Fourth Proportional to 1.29, 1.78 and 1.20

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Solution

The fourth proportional to 1.29, 1.78 and 1.20 is: 1.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    1.29 : 1.78 = 1.20 : x
  2. Step 2: Convert to fraction form
    1.29/1.78 = 1.20/x
  3. Step 3: Cross multiply
    1.29x = 1.78 × 1.20
  4. Step 4: Simplify right side
    1.29x = 2.14
  5. Step 5: Solve for x
    x = 2.14/1.29
  6. Step 6: Final answer
    x = 1.66

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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.