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Finding the Fourth Proportional to 0.80, 1.20 and 0.30

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Solution

The fourth proportional to 0.80, 1.20 and 0.30 is: 0.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    0.80 : 1.20 = 0.30 : x
  2. Step 2: Convert to fraction form
    0.80/1.20 = 0.30/x
  3. Step 3: Cross multiply
    0.80x = 1.20 × 0.30
  4. Step 4: Simplify right side
    0.80x = 0.36
  5. Step 5: Solve for x
    x = 0.36/0.80
  6. Step 6: Final answer
    x = 0.45

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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.