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Finding the Fourth Proportional to 48.21, 72.30 and 21.15

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Solution

The fourth proportional to 48.21, 72.30 and 21.15 is: 31.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    48.21 : 72.30 = 21.15 : x
  2. Step 2: Convert to fraction form
    48.21/72.30 = 21.15/x
  3. Step 3: Cross multiply
    48.21x = 72.30 × 21.15
  4. Step 4: Simplify right side
    48.21x = 1,529.15
  5. Step 5: Solve for x
    x = 1,529.15/48.21
  6. Step 6: Final answer
    x = 31.72

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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.