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Finding the Fourth Proportional to 1,345, 1,856.31 and 821.34

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Solution

The fourth proportional to 1,345, 1,856.31 and 821.34 is: 1,133.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,345 : 1,856.31 = 821.34 : x
  2. Step 2: Convert to fraction form
    1,345/1,856.31 = 821.34/x
  3. Step 3: Cross multiply
    1,345x = 1,856.31 × 821.34
  4. Step 4: Simplify right side
    1,345x = 1,524,648.27
  5. Step 5: Solve for x
    x = 1,524,648.27/1,345
  6. Step 6: Final answer
    x = 1,133.57

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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.