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Finding the Fourth Proportional to 690.30, 1,036.65 and 668.70

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Solution

The fourth proportional to 690.30, 1,036.65 and 668.70 is: 1,004.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.30 : 1,036.65 = 668.70 : x
  2. Step 2: Convert to fraction form
    690.30/1,036.65 = 668.70/x
  3. Step 3: Cross multiply
    690.30x = 1,036.65 × 668.70
  4. Step 4: Simplify right side
    690.30x = 693,207.86
  5. Step 5: Solve for x
    x = 693,207.86/690.30
  6. Step 6: Final answer
    x = 1,004.21

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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.