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Finding the Fourth Proportional to 690.42, 1,039.36 and 630.90

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Solution

The fourth proportional to 690.42, 1,039.36 and 630.90 is: 949.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.42 : 1,039.36 = 630.90 : x
  2. Step 2: Convert to fraction form
    690.42/1,039.36 = 630.90/x
  3. Step 3: Cross multiply
    690.42x = 1,039.36 × 630.90
  4. Step 4: Simplify right side
    690.42x = 655,732.22
  5. Step 5: Solve for x
    x = 655,732.22/690.42
  6. Step 6: Final answer
    x = 949.76

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.