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Finding the Fourth Proportional to 784.80, 1,171.80 and 770.40

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Solution

The fourth proportional to 784.80, 1,171.80 and 770.40 is: 1,150.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    784.80 : 1,171.80 = 770.40 : x
  2. Step 2: Convert to fraction form
    784.80/1,171.80 = 770.40/x
  3. Step 3: Cross multiply
    784.80x = 1,171.80 × 770.40
  4. Step 4: Simplify right side
    784.80x = 902,754.72
  5. Step 5: Solve for x
    x = 902,754.72/784.80
  6. Step 6: Final answer
    x = 1,150.30

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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.