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Finding the Fourth Proportional to 830.21, 1,245.30 and 213.91

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Solution

The fourth proportional to 830.21, 1,245.30 and 213.91 is: 320.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    830.21 : 1,245.30 = 213.91 : x
  2. Step 2: Convert to fraction form
    830.21/1,245.30 = 213.91/x
  3. Step 3: Cross multiply
    830.21x = 1,245.30 × 213.91
  4. Step 4: Simplify right side
    830.21x = 266,378.47
  5. Step 5: Solve for x
    x = 266,378.47/830.21
  6. Step 6: Final answer
    x = 320.86

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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.