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Finding the Fourth Proportional to 48.12, 72.13 and 21.05

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Solution

The fourth proportional to 48.12, 72.13 and 21.05 is: 31.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    48.12 : 72.13 = 21.05 : x
  2. Step 2: Convert to fraction form
    48.12/72.13 = 21.05/x
  3. Step 3: Cross multiply
    48.12x = 72.13 × 21.05
  4. Step 4: Simplify right side
    48.12x = 1,518.34
  5. Step 5: Solve for x
    x = 1,518.34/48.12
  6. Step 6: Final answer
    x = 31.55

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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.