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Finding the Fourth Proportional to 990.81, 1,487.30 and 414.09

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Solution

The fourth proportional to 990.81, 1,487.30 and 414.09 is: 621.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.81 : 1,487.30 = 414.09 : x
  2. Step 2: Convert to fraction form
    990.81/1,487.30 = 414.09/x
  3. Step 3: Cross multiply
    990.81x = 1,487.30 × 414.09
  4. Step 4: Simplify right side
    990.81x = 615,873.99
  5. Step 5: Solve for x
    x = 615,873.99/990.81
  6. Step 6: Final answer
    x = 621.59

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.