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Finding the Fourth Proportional to 779.99, 1,076.15 and 485.15

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Solution

The fourth proportional to 779.99, 1,076.15 and 485.15 is: 669.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    779.99 : 1,076.15 = 485.15 : x
  2. Step 2: Convert to fraction form
    779.99/1,076.15 = 485.15/x
  3. Step 3: Cross multiply
    779.99x = 1,076.15 × 485.15
  4. Step 4: Simplify right side
    779.99x = 522,090.00
  5. Step 5: Solve for x
    x = 522,090.00/779.99
  6. Step 6: Final answer
    x = 669.36

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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.