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Finding the Fourth Proportional to 642.80, 962.85 and 505.19

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Solution

The fourth proportional to 642.80, 962.85 and 505.19 is: 756.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.80 : 962.85 = 505.19 : x
  2. Step 2: Convert to fraction form
    642.80/962.85 = 505.19/x
  3. Step 3: Cross multiply
    642.80x = 962.85 × 505.19
  4. Step 4: Simplify right side
    642.80x = 486,422.19
  5. Step 5: Solve for x
    x = 486,422.19/642.80
  6. Step 6: Final answer
    x = 756.72

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.