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Finding the Fourth Proportional to 990.63, 1,485.88 and 260.21

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Solution

The fourth proportional to 990.63, 1,485.88 and 260.21 is: 390.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.63 : 1,485.88 = 260.21 : x
  2. Step 2: Convert to fraction form
    990.63/1,485.88 = 260.21/x
  3. Step 3: Cross multiply
    990.63x = 1,485.88 × 260.21
  4. Step 4: Simplify right side
    990.63x = 386,643.90
  5. Step 5: Solve for x
    x = 386,643.90/990.63
  6. Step 6: Final answer
    x = 390.30

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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.