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Finding the Fourth Proportional to 690.12, 1,035.40 and 203.20

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Solution

The fourth proportional to 690.12, 1,035.40 and 203.20 is: 304.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.12 : 1,035.40 = 203.20 : x
  2. Step 2: Convert to fraction form
    690.12/1,035.40 = 203.20/x
  3. Step 3: Cross multiply
    690.12x = 1,035.40 × 203.20
  4. Step 4: Simplify right side
    690.12x = 210,393.28
  5. Step 5: Solve for x
    x = 210,393.28/690.12
  6. Step 6: Final answer
    x = 304.86

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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.