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Finding the Fourth Proportional to 1,287, 1,775.10 and 815.16

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Solution

The fourth proportional to 1,287, 1,775.10 and 815.16 is: 1,124.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,287 : 1,775.10 = 815.16 : x
  2. Step 2: Convert to fraction form
    1,287/1,775.10 = 815.16/x
  3. Step 3: Cross multiply
    1,287x = 1,775.10 × 815.16
  4. Step 4: Simplify right side
    1,287x = 1,446,990.52
  5. Step 5: Solve for x
    x = 1,446,990.52/1,287
  6. Step 6: Final answer
    x = 1,124.31

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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.