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Finding the Fourth Proportional to 1,555, 2,145.90 and 856.39

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Solution

The fourth proportional to 1,555, 2,145.90 and 856.39 is: 1,181.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,555 : 2,145.90 = 856.39 : x
  2. Step 2: Convert to fraction form
    1,555/2,145.90 = 856.39/x
  3. Step 3: Cross multiply
    1,555x = 2,145.90 × 856.39
  4. Step 4: Simplify right side
    1,555x = 1,837,727.30
  5. Step 5: Solve for x
    x = 1,837,727.30/1,555
  6. Step 6: Final answer
    x = 1,181.82

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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.