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Finding the Fourth Proportional to 42.82, 64.26 and 21.16

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Solution

The fourth proportional to 42.82, 64.26 and 21.16 is: 31.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    42.82 : 64.26 = 21.16 : x
  2. Step 2: Convert to fraction form
    42.82/64.26 = 21.16/x
  3. Step 3: Cross multiply
    42.82x = 64.26 × 21.16
  4. Step 4: Simplify right side
    42.82x = 1,359.74
  5. Step 5: Solve for x
    x = 1,359.74/42.82
  6. Step 6: Final answer
    x = 31.75

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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.