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Finding the Fourth Proportional to 57.85, 79.81 and 39.40

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Solution

The fourth proportional to 57.85, 79.81 and 39.40 is: 54.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    57.85 : 79.81 = 39.40 : x
  2. Step 2: Convert to fraction form
    57.85/79.81 = 39.40/x
  3. Step 3: Cross multiply
    57.85x = 79.81 × 39.40
  4. Step 4: Simplify right side
    57.85x = 3,144.51
  5. Step 5: Solve for x
    x = 3,144.51/57.85
  6. Step 6: Final answer
    x = 54.36

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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.