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Finding the Fourth Proportional to 784.80, 1,177.61 and 419.70

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Solution

The fourth proportional to 784.80, 1,177.61 and 419.70 is: 629.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    784.80 : 1,177.61 = 419.70 : x
  2. Step 2: Convert to fraction form
    784.80/1,177.61 = 419.70/x
  3. Step 3: Cross multiply
    784.80x = 1,177.61 × 419.70
  4. Step 4: Simplify right side
    784.80x = 494,240.82
  5. Step 5: Solve for x
    x = 494,240.82/784.80
  6. Step 6: Final answer
    x = 629.77

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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.