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Finding the Fourth Proportional to 777.36, 1,072.80 and 428.08

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Solution

The fourth proportional to 777.36, 1,072.80 and 428.08 is: 590.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    777.36 : 1,072.80 = 428.08 : x
  2. Step 2: Convert to fraction form
    777.36/1,072.80 = 428.08/x
  3. Step 3: Cross multiply
    777.36x = 1,072.80 × 428.08
  4. Step 4: Simplify right side
    777.36x = 459,244.22
  5. Step 5: Solve for x
    x = 459,244.22/777.36
  6. Step 6: Final answer
    x = 590.77

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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.