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Finding the Fourth Proportional to 71.44, 98.40 and 56.80

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Solution

The fourth proportional to 71.44, 98.40 and 56.80 is: 78.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.44 : 98.40 = 56.80 : x
  2. Step 2: Convert to fraction form
    71.44/98.40 = 56.80/x
  3. Step 3: Cross multiply
    71.44x = 98.40 × 56.80
  4. Step 4: Simplify right side
    71.44x = 5,589.12
  5. Step 5: Solve for x
    x = 5,589.12/71.44
  6. Step 6: Final answer
    x = 78.24

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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.