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Finding the Fourth Proportional to 1,511, 2,085.20 and 890

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Solution

The fourth proportional to 1,511, 2,085.20 and 890 is: 1,228.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,511 : 2,085.20 = 890 : x
  2. Step 2: Convert to fraction form
    1,511/2,085.20 = 890/x
  3. Step 3: Cross multiply
    1,511x = 2,085.20 × 890
  4. Step 4: Simplify right side
    1,511x = 1,855,828.00
  5. Step 5: Solve for x
    x = 1,855,828.00/1,511
  6. Step 6: Final answer
    x = 1,228.21

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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.