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Finding the Fourth Proportional to 485, 669.30 and 278

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Solution

The fourth proportional to 485, 669.30 and 278 is: 383.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    485 : 669.30 = 278 : x
  2. Step 2: Convert to fraction form
    485/669.30 = 278/x
  3. Step 3: Cross multiply
    485x = 669.30 × 278
  4. Step 4: Simplify right side
    485x = 186,065.40
  5. Step 5: Solve for x
    x = 186,065.40/485
  6. Step 6: Final answer
    x = 383.64

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.