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Finding the Fourth Proportional to 786.65, 1,085.43 and 455.05

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Solution

The fourth proportional to 786.65, 1,085.43 and 455.05 is: 627.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    786.65 : 1,085.43 = 455.05 : x
  2. Step 2: Convert to fraction form
    786.65/1,085.43 = 455.05/x
  3. Step 3: Cross multiply
    786.65x = 1,085.43 × 455.05
  4. Step 4: Simplify right side
    786.65x = 493,927.98
  5. Step 5: Solve for x
    x = 493,927.98/786.65
  6. Step 6: Final answer
    x = 627.89

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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.