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Finding the Fourth Proportional to 71.68, 98.74 and 57.12

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Solution

The fourth proportional to 71.68, 98.74 and 57.12 is: 78.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.68 : 98.74 = 57.12 : x
  2. Step 2: Convert to fraction form
    71.68/98.74 = 57.12/x
  3. Step 3: Cross multiply
    71.68x = 98.74 × 57.12
  4. Step 4: Simplify right side
    71.68x = 5,640.03
  5. Step 5: Solve for x
    x = 5,640.03/71.68
  6. Step 6: Final answer
    x = 78.68

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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.