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Finding the Fourth Proportional to 40.80, 56.31 and 31.08

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Solution

The fourth proportional to 40.80, 56.31 and 31.08 is: 42.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    40.80 : 56.31 = 31.08 : x
  2. Step 2: Convert to fraction form
    40.80/56.31 = 31.08/x
  3. Step 3: Cross multiply
    40.80x = 56.31 × 31.08
  4. Step 4: Simplify right side
    40.80x = 1,750.11
  5. Step 5: Solve for x
    x = 1,750.11/40.80
  6. Step 6: Final answer
    x = 42.89

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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.