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Finding the Fourth Proportional to 690.40, 1,034.88 and 279.25

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Solution

The fourth proportional to 690.40, 1,034.88 and 279.25 is: 418.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.40 : 1,034.88 = 279.25 : x
  2. Step 2: Convert to fraction form
    690.40/1,034.88 = 279.25/x
  3. Step 3: Cross multiply
    690.40x = 1,034.88 × 279.25
  4. Step 4: Simplify right side
    690.40x = 288,990.24
  5. Step 5: Solve for x
    x = 288,990.24/690.40
  6. Step 6: Final answer
    x = 418.58

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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.