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Finding the Fourth Proportional to 777.40, 1,072.81 and 428.08

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Solution

The fourth proportional to 777.40, 1,072.81 and 428.08 is: 590.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    777.40 : 1,072.81 = 428.08 : x
  2. Step 2: Convert to fraction form
    777.40/1,072.81 = 428.08/x
  3. Step 3: Cross multiply
    777.40x = 1,072.81 × 428.08
  4. Step 4: Simplify right side
    777.40x = 459,248.50
  5. Step 5: Solve for x
    x = 459,248.50/777.40
  6. Step 6: Final answer
    x = 590.75

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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.