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Finding the Fourth Proportional to 690.83, 1,036.21 and 280

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Solution

The fourth proportional to 690.83, 1,036.21 and 280 is: 419.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.83 : 1,036.21 = 280 : x
  2. Step 2: Convert to fraction form
    690.83/1,036.21 = 280/x
  3. Step 3: Cross multiply
    690.83x = 1,036.21 × 280
  4. Step 4: Simplify right side
    690.83x = 290,137.40
  5. Step 5: Solve for x
    x = 290,137.40/690.83
  6. Step 6: Final answer
    x = 419.98

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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.