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Finding the Fourth Proportional to 784.65, 1,176.96 and 420.15

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Solution

The fourth proportional to 784.65, 1,176.96 and 420.15 is: 630.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    784.65 : 1,176.96 = 420.15 : x
  2. Step 2: Convert to fraction form
    784.65/1,176.96 = 420.15/x
  3. Step 3: Cross multiply
    784.65x = 1,176.96 × 420.15
  4. Step 4: Simplify right side
    784.65x = 494,505.73
  5. Step 5: Solve for x
    x = 494,505.73/784.65
  6. Step 6: Final answer
    x = 630.22

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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.