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Finding the Fourth Proportional to 56.81, 78.40 and 30.94

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Solution

The fourth proportional to 56.81, 78.40 and 30.94 is: 42.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    56.81 : 78.40 = 30.94 : x
  2. Step 2: Convert to fraction form
    56.81/78.40 = 30.94/x
  3. Step 3: Cross multiply
    56.81x = 78.40 × 30.94
  4. Step 4: Simplify right side
    56.81x = 2,425.54
  5. Step 5: Solve for x
    x = 2,425.54/56.81
  6. Step 6: Final answer
    x = 42.69

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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.