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Finding the Fourth Proportional to 991.30, 1,485.67 and 405.62

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Solution

The fourth proportional to 991.30, 1,485.67 and 405.62 is: 607.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    991.30 : 1,485.67 = 405.62 : x
  2. Step 2: Convert to fraction form
    991.30/1,485.67 = 405.62/x
  3. Step 3: Cross multiply
    991.30x = 1,485.67 × 405.62
  4. Step 4: Simplify right side
    991.30x = 602,617.47
  5. Step 5: Solve for x
    x = 602,617.47/991.30
  6. Step 6: Final answer
    x = 607.91

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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.