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Finding the Fourth Proportional to 990.62, 1,485.81 and 260.25

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Solution

The fourth proportional to 990.62, 1,485.81 and 260.25 is: 390.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.62 : 1,485.81 = 260.25 : x
  2. Step 2: Convert to fraction form
    990.62/1,485.81 = 260.25/x
  3. Step 3: Cross multiply
    990.62x = 1,485.81 × 260.25
  4. Step 4: Simplify right side
    990.62x = 386,682.05
  5. Step 5: Solve for x
    x = 386,682.05/990.62
  6. Step 6: Final answer
    x = 390.34

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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.