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Finding the Fourth Proportional to 777.31, 1,072.70 and 428.01

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Solution

The fourth proportional to 777.31, 1,072.70 and 428.01 is: 590.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    777.31 : 1,072.70 = 428.01 : x
  2. Step 2: Convert to fraction form
    777.31/1,072.70 = 428.01/x
  3. Step 3: Cross multiply
    777.31x = 1,072.70 × 428.01
  4. Step 4: Simplify right side
    777.31x = 459,124.19
  5. Step 5: Solve for x
    x = 459,124.19/777.31
  6. Step 6: Final answer
    x = 590.66

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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.