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Finding the Fourth Proportional to 103.80, 156.27 and 79.86

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Solution

The fourth proportional to 103.80, 156.27 and 79.86 is: 120.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.80 : 156.27 = 79.86 : x
  2. Step 2: Convert to fraction form
    103.80/156.27 = 79.86/x
  3. Step 3: Cross multiply
    103.80x = 156.27 × 79.86
  4. Step 4: Simplify right side
    103.80x = 12,479.72
  5. Step 5: Solve for x
    x = 12,479.72/103.80
  6. Step 6: Final answer
    x = 120.23

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.