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Finding the Fourth Proportional to 430.28, 645.42 and 137.79

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Solution

The fourth proportional to 430.28, 645.42 and 137.79 is: 206.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    430.28 : 645.42 = 137.79 : x
  2. Step 2: Convert to fraction form
    430.28/645.42 = 137.79/x
  3. Step 3: Cross multiply
    430.28x = 645.42 × 137.79
  4. Step 4: Simplify right side
    430.28x = 88,932.42
  5. Step 5: Solve for x
    x = 88,932.42/430.28
  6. Step 6: Final answer
    x = 206.69

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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.