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Finding the Fourth Proportional to 105.56, 145.60 and 72.80

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Solution

The fourth proportional to 105.56, 145.60 and 72.80 is: 100.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    105.56 : 145.60 = 72.80 : x
  2. Step 2: Convert to fraction form
    105.56/145.60 = 72.80/x
  3. Step 3: Cross multiply
    105.56x = 145.60 × 72.80
  4. Step 4: Simplify right side
    105.56x = 10,599.68
  5. Step 5: Solve for x
    x = 10,599.68/105.56
  6. Step 6: Final answer
    x = 100.41

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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.