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Finding the Fourth Proportional to 690.11, 1,037.21 and 639.18

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Solution

The fourth proportional to 690.11, 1,037.21 and 639.18 is: 960.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.11 : 1,037.21 = 639.18 : x
  2. Step 2: Convert to fraction form
    690.11/1,037.21 = 639.18/x
  3. Step 3: Cross multiply
    690.11x = 1,037.21 × 639.18
  4. Step 4: Simplify right side
    690.11x = 662,960.69
  5. Step 5: Solve for x
    x = 662,960.69/690.11
  6. Step 6: Final answer
    x = 960.67

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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.