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Finding the Fourth Proportional to 813.60, 1,220.40 and 778.05

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Solution

The fourth proportional to 813.60, 1,220.40 and 778.05 is: 1,167.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.60 : 1,220.40 = 778.05 : x
  2. Step 2: Convert to fraction form
    813.60/1,220.40 = 778.05/x
  3. Step 3: Cross multiply
    813.60x = 1,220.40 × 778.05
  4. Step 4: Simplify right side
    813.60x = 949,532.22
  5. Step 5: Solve for x
    x = 949,532.22/813.60
  6. Step 6: Final answer
    x = 1,167.08

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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.