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Finding the Fourth Proportional to 117.69, 162.30 and 80.78

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Solution

The fourth proportional to 117.69, 162.30 and 80.78 is: 111.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    117.69 : 162.30 = 80.78 : x
  2. Step 2: Convert to fraction form
    117.69/162.30 = 80.78/x
  3. Step 3: Cross multiply
    117.69x = 162.30 × 80.78
  4. Step 4: Simplify right side
    117.69x = 13,109.78
  5. Step 5: Solve for x
    x = 13,109.78/117.69
  6. Step 6: Final answer
    x = 111.39

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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.