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Finding the Fourth Proportional to 2,163, 2,985 and 1,218.78

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Solution

The fourth proportional to 2,163, 2,985 and 1,218.78 is: 1,681.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    2,163 : 2,985 = 1,218.78 : x
  2. Step 2: Convert to fraction form
    2,163/2,985 = 1,218.78/x
  3. Step 3: Cross multiply
    2,163x = 2,985 × 1,218.78
  4. Step 4: Simplify right side
    2,163x = 3,638,058.30
  5. Step 5: Solve for x
    x = 3,638,058.30/2,163
  6. Step 6: Final answer
    x = 1,681.95

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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.