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Finding the Fourth Proportional to 57.08, 78.77 and 31.21

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Solution

The fourth proportional to 57.08, 78.77 and 31.21 is: 43.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    57.08 : 78.77 = 31.21 : x
  2. Step 2: Convert to fraction form
    57.08/78.77 = 31.21/x
  3. Step 3: Cross multiply
    57.08x = 78.77 × 31.21
  4. Step 4: Simplify right side
    57.08x = 2,458.02
  5. Step 5: Solve for x
    x = 2,458.02/57.08
  6. Step 6: Final answer
    x = 43.06

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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.