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Finding the Fourth Proportional to 718.20, 990.90 and 455.76

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Solution

The fourth proportional to 718.20, 990.90 and 455.76 is: 628.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    718.20 : 990.90 = 455.76 : x
  2. Step 2: Convert to fraction form
    718.20/990.90 = 455.76/x
  3. Step 3: Cross multiply
    718.20x = 990.90 × 455.76
  4. Step 4: Simplify right side
    718.20x = 451,612.58
  5. Step 5: Solve for x
    x = 451,612.58/718.20
  6. Step 6: Final answer
    x = 628.81

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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.