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Finding the Fourth Proportional to 856.94, 1,284.61 and 780.86

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Solution

The fourth proportional to 856.94, 1,284.61 and 780.86 is: 1,170.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    856.94 : 1,284.61 = 780.86 : x
  2. Step 2: Convert to fraction form
    856.94/1,284.61 = 780.86/x
  3. Step 3: Cross multiply
    856.94x = 1,284.61 × 780.86
  4. Step 4: Simplify right side
    856.94x = 1,003,100.56
  5. Step 5: Solve for x
    x = 1,003,100.56/856.94
  6. Step 6: Final answer
    x = 1,170.56

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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.