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Finding the Fourth Proportional to 807.80, 1,211.70 and 615.80

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Solution

The fourth proportional to 807.80, 1,211.70 and 615.80 is: 923.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    807.80 : 1,211.70 = 615.80 : x
  2. Step 2: Convert to fraction form
    807.80/1,211.70 = 615.80/x
  3. Step 3: Cross multiply
    807.80x = 1,211.70 × 615.80
  4. Step 4: Simplify right side
    807.80x = 746,164.86
  5. Step 5: Solve for x
    x = 746,164.86/807.80
  6. Step 6: Final answer
    x = 923.70

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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.