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Finding the Fourth Proportional to 690.39, 1,035.59 and 203.78

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Solution

The fourth proportional to 690.39, 1,035.59 and 203.78 is: 305.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.39 : 1,035.59 = 203.78 : x
  2. Step 2: Convert to fraction form
    690.39/1,035.59 = 203.78/x
  3. Step 3: Cross multiply
    690.39x = 1,035.59 × 203.78
  4. Step 4: Simplify right side
    690.39x = 211,034.10
  5. Step 5: Solve for x
    x = 211,034.10/690.39
  6. Step 6: Final answer
    x = 305.67

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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.