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Finding the Fourth Proportional to 142.36, 213.50 and 69.21

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Solution

The fourth proportional to 142.36, 213.50 and 69.21 is: 103.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.36 : 213.50 = 69.21 : x
  2. Step 2: Convert to fraction form
    142.36/213.50 = 69.21/x
  3. Step 3: Cross multiply
    142.36x = 213.50 × 69.21
  4. Step 4: Simplify right side
    142.36x = 14,776.51
  5. Step 5: Solve for x
    x = 14,776.51/142.36
  6. Step 6: Final answer
    x = 103.80

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.