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Finding the Fourth Proportional to 990.99, 1,485.65 and 398.07

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Solution

The fourth proportional to 990.99, 1,485.65 and 398.07 is: 596.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.99 : 1,485.65 = 398.07 : x
  2. Step 2: Convert to fraction form
    990.99/1,485.65 = 398.07/x
  3. Step 3: Cross multiply
    990.99x = 1,485.65 × 398.07
  4. Step 4: Simplify right side
    990.99x = 591,390.71
  5. Step 5: Solve for x
    x = 591,390.71/990.99
  6. Step 6: Final answer
    x = 596.77

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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.