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Finding the Fourth Proportional to 101.25, 139.78 and 72.19

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Solution

The fourth proportional to 101.25, 139.78 and 72.19 is: 99.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    101.25 : 139.78 = 72.19 : x
  2. Step 2: Convert to fraction form
    101.25/139.78 = 72.19/x
  3. Step 3: Cross multiply
    101.25x = 139.78 × 72.19
  4. Step 4: Simplify right side
    101.25x = 10,090.58
  5. Step 5: Solve for x
    x = 10,090.58/101.25
  6. Step 6: Final answer
    x = 99.66

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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.