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Finding the Fourth Proportional to 78.05, 117.69 and 73.80

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Solution

The fourth proportional to 78.05, 117.69 and 73.80 is: 111.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.05 : 117.69 = 73.80 : x
  2. Step 2: Convert to fraction form
    78.05/117.69 = 73.80/x
  3. Step 3: Cross multiply
    78.05x = 117.69 × 73.80
  4. Step 4: Simplify right side
    78.05x = 8,685.52
  5. Step 5: Solve for x
    x = 8,685.52/78.05
  6. Step 6: Final answer
    x = 111.29

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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.