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Finding the Fourth Proportional to 109.70, 151.29 and 78.60

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Solution

The fourth proportional to 109.70, 151.29 and 78.60 is: 108.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    109.70 : 151.29 = 78.60 : x
  2. Step 2: Convert to fraction form
    109.70/151.29 = 78.60/x
  3. Step 3: Cross multiply
    109.70x = 151.29 × 78.60
  4. Step 4: Simplify right side
    109.70x = 11,891.39
  5. Step 5: Solve for x
    x = 11,891.39/109.70
  6. Step 6: Final answer
    x = 108.40

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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.