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Finding the Fourth Proportional to 990.56, 1,485.80 and 260.12

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Solution

The fourth proportional to 990.56, 1,485.80 and 260.12 is: 390.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.56 : 1,485.80 = 260.12 : x
  2. Step 2: Convert to fraction form
    990.56/1,485.80 = 260.12/x
  3. Step 3: Cross multiply
    990.56x = 1,485.80 × 260.12
  4. Step 4: Simplify right side
    990.56x = 386,486.30
  5. Step 5: Solve for x
    x = 386,486.30/990.56
  6. Step 6: Final answer
    x = 390.17

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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.