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Finding the Fourth Proportional to 679.80, 1,019.60 and 328.20

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Solution

The fourth proportional to 679.80, 1,019.60 and 328.20 is: 492.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    679.80 : 1,019.60 = 328.20 : x
  2. Step 2: Convert to fraction form
    679.80/1,019.60 = 328.20/x
  3. Step 3: Cross multiply
    679.80x = 1,019.60 × 328.20
  4. Step 4: Simplify right side
    679.80x = 334,632.72
  5. Step 5: Solve for x
    x = 334,632.72/679.80
  6. Step 6: Final answer
    x = 492.25

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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.