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Finding the Fourth Proportional to 777.32, 1,072.70 and 428

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Solution

The fourth proportional to 777.32, 1,072.70 and 428 is: 590.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    777.32 : 1,072.70 = 428 : x
  2. Step 2: Convert to fraction form
    777.32/1,072.70 = 428/x
  3. Step 3: Cross multiply
    777.32x = 1,072.70 × 428
  4. Step 4: Simplify right side
    777.32x = 459,115.60
  5. Step 5: Solve for x
    x = 459,115.60/777.32
  6. Step 6: Final answer
    x = 590.64

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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.