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Finding the Fourth Proportional to 103.21, 142.51 and 77.28

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Solution

The fourth proportional to 103.21, 142.51 and 77.28 is: 106.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.21 : 142.51 = 77.28 : x
  2. Step 2: Convert to fraction form
    103.21/142.51 = 77.28/x
  3. Step 3: Cross multiply
    103.21x = 142.51 × 77.28
  4. Step 4: Simplify right side
    103.21x = 11,012.07
  5. Step 5: Solve for x
    x = 11,012.07/103.21
  6. Step 6: Final answer
    x = 106.70

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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.