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Finding the Third Proportional to 0.18 and 0.21

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Solution

The third proportional to 0.18 and 0.21 is: 0.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    0.18 : 0.21 = 0.21 : x
  2. Step 2: Convert to fraction form
    0.18/0.21 = 0.21/x
  3. Step 3: Cross multiply
    0.18x = 0.21 × 0.21
  4. Step 4: Simplify right side
    0.18x = 0.04
  5. Step 5: Solve for x
    x = 0.04/0.18
  6. Step 6: Final answer
    x = 0.25

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Why These Related Problems?

These problems maintain the same ratio (1.20) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.