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Finding the Fourth Proportional to 786.90, 1,084.44 and 646.20

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Solution

The fourth proportional to 786.90, 1,084.44 and 646.20 is: 890.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    786.90 : 1,084.44 = 646.20 : x
  2. Step 2: Convert to fraction form
    786.90/1,084.44 = 646.20/x
  3. Step 3: Cross multiply
    786.90x = 1,084.44 × 646.20
  4. Step 4: Simplify right side
    786.90x = 700,765.13
  5. Step 5: Solve for x
    x = 700,765.13/786.90
  6. Step 6: Final answer
    x = 890.54

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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.