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Finding the Fourth Proportional to 790.28, 1,186.34 and 425.78

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Solution

The fourth proportional to 790.28, 1,186.34 and 425.78 is: 639.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    790.28 : 1,186.34 = 425.78 : x
  2. Step 2: Convert to fraction form
    790.28/1,186.34 = 425.78/x
  3. Step 3: Cross multiply
    790.28x = 1,186.34 × 425.78
  4. Step 4: Simplify right side
    790.28x = 505,116.23
  5. Step 5: Solve for x
    x = 505,116.23/790.28
  6. Step 6: Final answer
    x = 639.16

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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.