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Finding the Fourth Proportional to 76.65, 105.78 and 43.90

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Solution

The fourth proportional to 76.65, 105.78 and 43.90 is: 60.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.65 : 105.78 = 43.90 : x
  2. Step 2: Convert to fraction form
    76.65/105.78 = 43.90/x
  3. Step 3: Cross multiply
    76.65x = 105.78 × 43.90
  4. Step 4: Simplify right side
    76.65x = 4,643.74
  5. Step 5: Solve for x
    x = 4,643.74/76.65
  6. Step 6: Final answer
    x = 60.59

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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.