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Finding the Fourth Proportional to 818.79, 1,228.88 and 407.80

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Solution

The fourth proportional to 818.79, 1,228.88 and 407.80 is: 612.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    818.79 : 1,228.88 = 407.80 : x
  2. Step 2: Convert to fraction form
    818.79/1,228.88 = 407.80/x
  3. Step 3: Cross multiply
    818.79x = 1,228.88 × 407.80
  4. Step 4: Simplify right side
    818.79x = 501,137.26
  5. Step 5: Solve for x
    x = 501,137.26/818.79
  6. Step 6: Final answer
    x = 612.05

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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.