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Finding the Fourth Proportional to 991.28, 1,485.30 and 580.75

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Solution

The fourth proportional to 991.28, 1,485.30 and 580.75 is: 870.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    991.28 : 1,485.30 = 580.75 : x
  2. Step 2: Convert to fraction form
    991.28/1,485.30 = 580.75/x
  3. Step 3: Cross multiply
    991.28x = 1,485.30 × 580.75
  4. Step 4: Simplify right side
    991.28x = 862,586.44
  5. Step 5: Solve for x
    x = 862,586.44/991.28
  6. Step 6: Final answer
    x = 870.17

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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.