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Finding the Fourth Proportional to 145.20, 200.40 and 103.72

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Solution

The fourth proportional to 145.20, 200.40 and 103.72 is: 143.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    145.20 : 200.40 = 103.72 : x
  2. Step 2: Convert to fraction form
    145.20/200.40 = 103.72/x
  3. Step 3: Cross multiply
    145.20x = 200.40 × 103.72
  4. Step 4: Simplify right side
    145.20x = 20,785.49
  5. Step 5: Solve for x
    x = 20,785.49/145.20
  6. Step 6: Final answer
    x = 143.15

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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.