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Finding the Fourth Proportional to 78.68, 108.61 and 57.78

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Solution

The fourth proportional to 78.68, 108.61 and 57.78 is: 79.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.68 : 108.61 = 57.78 : x
  2. Step 2: Convert to fraction form
    78.68/108.61 = 57.78/x
  3. Step 3: Cross multiply
    78.68x = 108.61 × 57.78
  4. Step 4: Simplify right side
    78.68x = 6,275.34
  5. Step 5: Solve for x
    x = 6,275.34/78.68
  6. Step 6: Final answer
    x = 79.76

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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.