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Finding the Fourth Proportional to 76.40, 105.43 and 50.21

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Solution

The fourth proportional to 76.40, 105.43 and 50.21 is: 69.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.40 : 105.43 = 50.21 : x
  2. Step 2: Convert to fraction form
    76.40/105.43 = 50.21/x
  3. Step 3: Cross multiply
    76.40x = 105.43 × 50.21
  4. Step 4: Simplify right side
    76.40x = 5,294.07
  5. Step 5: Solve for x
    x = 5,294.07/76.40
  6. Step 6: Final answer
    x = 69.30

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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.