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Finding the Fourth Proportional to 779.48, 1,074.65 and 646.20

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Solution

The fourth proportional to 779.48, 1,074.65 and 646.20 is: 890.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    779.48 : 1,074.65 = 646.20 : x
  2. Step 2: Convert to fraction form
    779.48/1,074.65 = 646.20/x
  3. Step 3: Cross multiply
    779.48x = 1,074.65 × 646.20
  4. Step 4: Simplify right side
    779.48x = 694,435.60
  5. Step 5: Solve for x
    x = 694,435.60/779.48
  6. Step 6: Final answer
    x = 890.90

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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.