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Finding the Fourth Proportional to 856.70, 1,284.24 and 780.61

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Solution

The fourth proportional to 856.70, 1,284.24 and 780.61 is: 1,170.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    856.70 : 1,284.24 = 780.61 : x
  2. Step 2: Convert to fraction form
    856.70/1,284.24 = 780.61/x
  3. Step 3: Cross multiply
    856.70x = 1,284.24 × 780.61
  4. Step 4: Simplify right side
    856.70x = 1,002,490.59
  5. Step 5: Solve for x
    x = 1,002,490.59/856.70
  6. Step 6: Final answer
    x = 1,170.18

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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.