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Finding the Fourth Proportional to 885.70, 1,218.54 and 861.40

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Solution

The fourth proportional to 885.70, 1,218.54 and 861.40 is: 1,185.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    885.70 : 1,218.54 = 861.40 : x
  2. Step 2: Convert to fraction form
    885.70/1,218.54 = 861.40/x
  3. Step 3: Cross multiply
    885.70x = 1,218.54 × 861.40
  4. Step 4: Simplify right side
    885.70x = 1,049,650.36
  5. Step 5: Solve for x
    x = 1,049,650.36/885.70
  6. Step 6: Final answer
    x = 1,185.11

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.