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Finding the Fourth Proportional to 40.28, 55.65 and 31.05

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Solution

The fourth proportional to 40.28, 55.65 and 31.05 is: 42.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    40.28 : 55.65 = 31.05 : x
  2. Step 2: Convert to fraction form
    40.28/55.65 = 31.05/x
  3. Step 3: Cross multiply
    40.28x = 55.65 × 31.05
  4. Step 4: Simplify right side
    40.28x = 1,728.14
  5. Step 5: Solve for x
    x = 1,728.14/40.28
  6. Step 6: Final answer
    x = 42.90

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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.