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Finding the Fourth Proportional to 990.12, 1,485.39 and 340.80

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Solution

The fourth proportional to 990.12, 1,485.39 and 340.80 is: 511.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.12 : 1,485.39 = 340.80 : x
  2. Step 2: Convert to fraction form
    990.12/1,485.39 = 340.80/x
  3. Step 3: Cross multiply
    990.12x = 1,485.39 × 340.80
  4. Step 4: Simplify right side
    990.12x = 506,220.91
  5. Step 5: Solve for x
    x = 506,220.91/990.12
  6. Step 6: Final answer
    x = 511.27

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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.