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Finding the Fourth Proportional to 777.50, 1,072.95 and 428.20

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Solution

The fourth proportional to 777.50, 1,072.95 and 428.20 is: 590.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    777.50 : 1,072.95 = 428.20 : x
  2. Step 2: Convert to fraction form
    777.50/1,072.95 = 428.20/x
  3. Step 3: Cross multiply
    777.50x = 1,072.95 × 428.20
  4. Step 4: Simplify right side
    777.50x = 459,437.19
  5. Step 5: Solve for x
    x = 459,437.19/777.50
  6. Step 6: Final answer
    x = 590.92

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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.