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Finding the Fourth Proportional to 990.66, 1,485.88 and 260.31

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Solution

The fourth proportional to 990.66, 1,485.88 and 260.31 is: 390.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.66 : 1,485.88 = 260.31 : x
  2. Step 2: Convert to fraction form
    990.66/1,485.88 = 260.31/x
  3. Step 3: Cross multiply
    990.66x = 1,485.88 × 260.31
  4. Step 4: Simplify right side
    990.66x = 386,794.34
  5. Step 5: Solve for x
    x = 386,794.34/990.66
  6. Step 6: Final answer
    x = 390.44

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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.