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Finding the Fourth Proportional to 31.02, 42.60 and 30.90

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Solution

The fourth proportional to 31.02, 42.60 and 30.90 is: 42.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.02 : 42.60 = 30.90 : x
  2. Step 2: Convert to fraction form
    31.02/42.60 = 30.90/x
  3. Step 3: Cross multiply
    31.02x = 42.60 × 30.90
  4. Step 4: Simplify right side
    31.02x = 1,316.34
  5. Step 5: Solve for x
    x = 1,316.34/31.02
  6. Step 6: Final answer
    x = 42.44

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.