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Finding the Fourth Proportional to 664.40, 917.26 and 487.21

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Solution

The fourth proportional to 664.40, 917.26 and 487.21 is: 672.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    664.40 : 917.26 = 487.21 : x
  2. Step 2: Convert to fraction form
    664.40/917.26 = 487.21/x
  3. Step 3: Cross multiply
    664.40x = 917.26 × 487.21
  4. Step 4: Simplify right side
    664.40x = 446,895.81
  5. Step 5: Solve for x
    x = 446,895.81/664.40
  6. Step 6: Final answer
    x = 672.64

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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.