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Finding the Fourth Proportional to 718.96, 991.38 and 485.68

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Solution

The fourth proportional to 718.96, 991.38 and 485.68 is: 669.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    718.96 : 991.38 = 485.68 : x
  2. Step 2: Convert to fraction form
    718.96/991.38 = 485.68/x
  3. Step 3: Cross multiply
    718.96x = 991.38 × 485.68
  4. Step 4: Simplify right side
    718.96x = 481,493.44
  5. Step 5: Solve for x
    x = 481,493.44/718.96
  6. Step 6: Final answer
    x = 669.71

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Double scale
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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.