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Finding the Fourth Proportional to 145.05, 216.28 and 139.78

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Solution

The fourth proportional to 145.05, 216.28 and 139.78 is: 208.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    145.05 : 216.28 = 139.78 : x
  2. Step 2: Convert to fraction form
    145.05/216.28 = 139.78/x
  3. Step 3: Cross multiply
    145.05x = 216.28 × 139.78
  4. Step 4: Simplify right side
    145.05x = 30,230.92
  5. Step 5: Solve for x
    x = 30,230.92/145.05
  6. Step 6: Final answer
    x = 208.42

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.