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Finding the Fourth Proportional to 990.80, 1,485.84 and 405.52

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Solution

The fourth proportional to 990.80, 1,485.84 and 405.52 is: 608.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.80 : 1,485.84 = 405.52 : x
  2. Step 2: Convert to fraction form
    990.80/1,485.84 = 405.52/x
  3. Step 3: Cross multiply
    990.80x = 1,485.84 × 405.52
  4. Step 4: Simplify right side
    990.80x = 602,537.84
  5. Step 5: Solve for x
    x = 602,537.84/990.80
  6. Step 6: Final answer
    x = 608.13

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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.