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Finding the Fourth Proportional to 79.78, 119.68 and 56.90

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Solution

The fourth proportional to 79.78, 119.68 and 56.90 is: 85.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.78 : 119.68 = 56.90 : x
  2. Step 2: Convert to fraction form
    79.78/119.68 = 56.90/x
  3. Step 3: Cross multiply
    79.78x = 119.68 × 56.90
  4. Step 4: Simplify right side
    79.78x = 6,809.79
  5. Step 5: Solve for x
    x = 6,809.79/79.78
  6. Step 6: Final answer
    x = 85.36

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.