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Finding the Fourth Proportional to 42.21, 58.28 and 31.28

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Solution

The fourth proportional to 42.21, 58.28 and 31.28 is: 43.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    42.21 : 58.28 = 31.28 : x
  2. Step 2: Convert to fraction form
    42.21/58.28 = 31.28/x
  3. Step 3: Cross multiply
    42.21x = 58.28 × 31.28
  4. Step 4: Simplify right side
    42.21x = 1,822.55
  5. Step 5: Solve for x
    x = 1,822.55/42.21
  6. Step 6: Final answer
    x = 43.18

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.