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Finding the Fourth Proportional to 790.80, 1,186.62 and 425.70

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Solution

The fourth proportional to 790.80, 1,186.62 and 425.70 is: 638.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    790.80 : 1,186.62 = 425.70 : x
  2. Step 2: Convert to fraction form
    790.80/1,186.62 = 425.70/x
  3. Step 3: Cross multiply
    790.80x = 1,186.62 × 425.70
  4. Step 4: Simplify right side
    790.80x = 505,144.13
  5. Step 5: Solve for x
    x = 505,144.13/790.80
  6. Step 6: Final answer
    x = 638.78

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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.