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Finding the Fourth Proportional to 861.63, 1,285.50 and 783.69

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Solution

The fourth proportional to 861.63, 1,285.50 and 783.69 is: 1,169.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.63 : 1,285.50 = 783.69 : x
  2. Step 2: Convert to fraction form
    861.63/1,285.50 = 783.69/x
  3. Step 3: Cross multiply
    861.63x = 1,285.50 × 783.69
  4. Step 4: Simplify right side
    861.63x = 1,007,433.50
  5. Step 5: Solve for x
    x = 1,007,433.50/861.63
  6. Step 6: Final answer
    x = 1,169.22

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.