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Finding the Fourth Proportional to 786.80, 1,085.83 and 455.31

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Solution

The fourth proportional to 786.80, 1,085.83 and 455.31 is: 628.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    786.80 : 1,085.83 = 455.31 : x
  2. Step 2: Convert to fraction form
    786.80/1,085.83 = 455.31/x
  3. Step 3: Cross multiply
    786.80x = 1,085.83 × 455.31
  4. Step 4: Simplify right side
    786.80x = 494,389.26
  5. Step 5: Solve for x
    x = 494,389.26/786.80
  6. Step 6: Final answer
    x = 628.35

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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.