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Finding the Fourth Proportional to 21.84, 32.56 and 21.18

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Solution

The fourth proportional to 21.84, 32.56 and 21.18 is: 31.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.84 : 32.56 = 21.18 : x
  2. Step 2: Convert to fraction form
    21.84/32.56 = 21.18/x
  3. Step 3: Cross multiply
    21.84x = 32.56 × 21.18
  4. Step 4: Simplify right side
    21.84x = 689.62
  5. Step 5: Solve for x
    x = 689.62/21.84
  6. Step 6: Final answer
    x = 31.58

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.