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Finding the Fourth Proportional to 786.86, 1,085.91 and 455.40

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Solution

The fourth proportional to 786.86, 1,085.91 and 455.40 is: 628.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    786.86 : 1,085.91 = 455.40 : x
  2. Step 2: Convert to fraction form
    786.86/1,085.91 = 455.40/x
  3. Step 3: Cross multiply
    786.86x = 1,085.91 × 455.40
  4. Step 4: Simplify right side
    786.86x = 494,521.71
  5. Step 5: Solve for x
    x = 494,521.71/786.86
  6. Step 6: Final answer
    x = 628.48

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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.