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Finding the Fourth Proportional to 830.20, 1,245.30 and 785.40

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Solution

The fourth proportional to 830.20, 1,245.30 and 785.40 is: 1,178.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    830.20 : 1,245.30 = 785.40 : x
  2. Step 2: Convert to fraction form
    830.20/1,245.30 = 785.40/x
  3. Step 3: Cross multiply
    830.20x = 1,245.30 × 785.40
  4. Step 4: Simplify right side
    830.20x = 978,058.62
  5. Step 5: Solve for x
    x = 978,058.62/830.20
  6. Step 6: Final answer
    x = 1,178.10

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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.