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Finding the Fourth Proportional to 786.98, 1,085.60 and 491.74

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Solution

The fourth proportional to 786.98, 1,085.60 and 491.74 is: 678.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    786.98 : 1,085.60 = 491.74 : x
  2. Step 2: Convert to fraction form
    786.98/1,085.60 = 491.74/x
  3. Step 3: Cross multiply
    786.98x = 1,085.60 × 491.74
  4. Step 4: Simplify right side
    786.98x = 533,832.94
  5. Step 5: Solve for x
    x = 533,832.94/786.98
  6. Step 6: Final answer
    x = 678.33

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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.