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Finding the Third Proportional to 390.84 and 858.57

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Solution

The third proportional to 390.84 and 858.57 is: 1,886.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.84 : 858.57 = 858.57 : x
  2. Step 2: Convert to fraction form
    390.84/858.57 = 858.57/x
  3. Step 3: Cross multiply
    390.84x = 858.57 × 858.57
  4. Step 4: Simplify right side
    390.84x = 737,139.63
  5. Step 5: Solve for x
    x = 737,139.63/390.84
  6. Step 6: Final answer
    x = 1,886.04

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Why These Related Problems?

These problems maintain the same ratio (2.20) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.