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Finding the Fourth Proportional to 125.28, 172.86 and 78.63

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Solution

The fourth proportional to 125.28, 172.86 and 78.63 is: 108.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    125.28 : 172.86 = 78.63 : x
  2. Step 2: Convert to fraction form
    125.28/172.86 = 78.63/x
  3. Step 3: Cross multiply
    125.28x = 172.86 × 78.63
  4. Step 4: Simplify right side
    125.28x = 13,591.98
  5. Step 5: Solve for x
    x = 13,591.98/125.28
  6. Step 6: Final answer
    x = 108.49

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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.