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Finding the Fourth Proportional to 77.60, 115.65 and 74.20

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Solution

The fourth proportional to 77.60, 115.65 and 74.20 is: 110.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.60 : 115.65 = 74.20 : x
  2. Step 2: Convert to fraction form
    77.60/115.65 = 74.20/x
  3. Step 3: Cross multiply
    77.60x = 115.65 × 74.20
  4. Step 4: Simplify right side
    77.60x = 8,581.23
  5. Step 5: Solve for x
    x = 8,581.23/77.60
  6. Step 6: Final answer
    x = 110.58

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.