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Finding the Fourth Proportional to 980.80, 1,353.40 and 648.64

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Solution

The fourth proportional to 980.80, 1,353.40 and 648.64 is: 895.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    980.80 : 1,353.40 = 648.64 : x
  2. Step 2: Convert to fraction form
    980.80/1,353.40 = 648.64/x
  3. Step 3: Cross multiply
    980.80x = 1,353.40 × 648.64
  4. Step 4: Simplify right side
    980.80x = 877,869.38
  5. Step 5: Solve for x
    x = 877,869.38/980.80
  6. Step 6: Final answer
    x = 895.05

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.