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Finding the Fourth Proportional to 806.78, 1,209.06 and 561.35

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Solution

The fourth proportional to 806.78, 1,209.06 and 561.35 is: 841.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    806.78 : 1,209.06 = 561.35 : x
  2. Step 2: Convert to fraction form
    806.78/1,209.06 = 561.35/x
  3. Step 3: Cross multiply
    806.78x = 1,209.06 × 561.35
  4. Step 4: Simplify right side
    806.78x = 678,708.85
  5. Step 5: Solve for x
    x = 678,708.85/806.78
  6. Step 6: Final answer
    x = 841.25

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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.