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Finding the Fourth Proportional to 72.49, 108.71 and 21.13

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Solution

The fourth proportional to 72.49, 108.71 and 21.13 is: 31.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.49 : 108.71 = 21.13 : x
  2. Step 2: Convert to fraction form
    72.49/108.71 = 21.13/x
  3. Step 3: Cross multiply
    72.49x = 108.71 × 21.13
  4. Step 4: Simplify right side
    72.49x = 2,297.04
  5. Step 5: Solve for x
    x = 2,297.04/72.49
  6. Step 6: Final answer
    x = 31.69

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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.