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Finding the Fourth Proportional to 777.63, 1,072.90 and 478.91

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Solution

The fourth proportional to 777.63, 1,072.90 and 478.91 is: 660.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    777.63 : 1,072.90 = 478.91 : x
  2. Step 2: Convert to fraction form
    777.63/1,072.90 = 478.91/x
  3. Step 3: Cross multiply
    777.63x = 1,072.90 × 478.91
  4. Step 4: Simplify right side
    777.63x = 513,823.13
  5. Step 5: Solve for x
    x = 513,823.13/777.63
  6. Step 6: Final answer
    x = 660.76

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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.