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Finding the Fourth Proportional to 990.19, 1,485.30 and 259.84

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Solution

The fourth proportional to 990.19, 1,485.30 and 259.84 is: 389.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.19 : 1,485.30 = 259.84 : x
  2. Step 2: Convert to fraction form
    990.19/1,485.30 = 259.84/x
  3. Step 3: Cross multiply
    990.19x = 1,485.30 × 259.84
  4. Step 4: Simplify right side
    990.19x = 385,940.35
  5. Step 5: Solve for x
    x = 385,940.35/990.19
  6. Step 6: Final answer
    x = 389.76

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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.