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Finding the Fourth Proportional to 980.64, 1,471.60 and 811.68

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Solution

The fourth proportional to 980.64, 1,471.60 and 811.68 is: 1,218.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    980.64 : 1,471.60 = 811.68 : x
  2. Step 2: Convert to fraction form
    980.64/1,471.60 = 811.68/x
  3. Step 3: Cross multiply
    980.64x = 1,471.60 × 811.68
  4. Step 4: Simplify right side
    980.64x = 1,194,468.29
  5. Step 5: Solve for x
    x = 1,194,468.29/980.64
  6. Step 6: Final answer
    x = 1,218.05

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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.