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Finding the Fourth Proportional to 684.45, 1,020.80 and 611.55

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Solution

The fourth proportional to 684.45, 1,020.80 and 611.55 is: 912.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    684.45 : 1,020.80 = 611.55 : x
  2. Step 2: Convert to fraction form
    684.45/1,020.80 = 611.55/x
  3. Step 3: Cross multiply
    684.45x = 1,020.80 × 611.55
  4. Step 4: Simplify right side
    684.45x = 624,271.77
  5. Step 5: Solve for x
    x = 624,271.77/684.45
  6. Step 6: Final answer
    x = 912.08

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.