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Finding the Fourth Proportional to 1,215.84, 1,675.84 and 861.31

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Solution

The fourth proportional to 1,215.84, 1,675.84 and 861.31 is: 1,187.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,215.84 : 1,675.84 = 861.31 : x
  2. Step 2: Convert to fraction form
    1,215.84/1,675.84 = 861.31/x
  3. Step 3: Cross multiply
    1,215.84x = 1,675.84 × 861.31
  4. Step 4: Simplify right side
    1,215.84x = 1,443,417.75
  5. Step 5: Solve for x
    x = 1,443,417.75/1,215.84
  6. Step 6: Final answer
    x = 1,187.18

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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.