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Finding the Fourth Proportional to 100.78, 151.21 and 70.33

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Solution

The fourth proportional to 100.78, 151.21 and 70.33 is: 105.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.78 : 151.21 = 70.33 : x
  2. Step 2: Convert to fraction form
    100.78/151.21 = 70.33/x
  3. Step 3: Cross multiply
    100.78x = 151.21 × 70.33
  4. Step 4: Simplify right side
    100.78x = 10,634.60
  5. Step 5: Solve for x
    x = 10,634.60/100.78
  6. Step 6: Final answer
    x = 105.52

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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.