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Finding the Fourth Proportional to 838.80, 1,258.20 and 771.60

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Solution

The fourth proportional to 838.80, 1,258.20 and 771.60 is: 1,157.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    838.80 : 1,258.20 = 771.60 : x
  2. Step 2: Convert to fraction form
    838.80/1,258.20 = 771.60/x
  3. Step 3: Cross multiply
    838.80x = 1,258.20 × 771.60
  4. Step 4: Simplify right side
    838.80x = 970,827.12
  5. Step 5: Solve for x
    x = 970,827.12/838.80
  6. Step 6: Final answer
    x = 1,157.40

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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.