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Finding the Fourth Proportional to 1,780.79, 2,669.96 and 856.78

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Solution

The fourth proportional to 1,780.79, 2,669.96 and 856.78 is: 1,284.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,780.79 : 2,669.96 = 856.78 : x
  2. Step 2: Convert to fraction form
    1,780.79/2,669.96 = 856.78/x
  3. Step 3: Cross multiply
    1,780.79x = 2,669.96 × 856.78
  4. Step 4: Simplify right side
    1,780.79x = 2,287,563.80
  5. Step 5: Solve for x
    x = 2,287,563.80/1,780.79
  6. Step 6: Final answer
    x = 1,284.58

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.