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Finding the Fourth Proportional to 780.02, 1,076.15 and 485.18

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Solution

The fourth proportional to 780.02, 1,076.15 and 485.18 is: 669.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.02 : 1,076.15 = 485.18 : x
  2. Step 2: Convert to fraction form
    780.02/1,076.15 = 485.18/x
  3. Step 3: Cross multiply
    780.02x = 1,076.15 × 485.18
  4. Step 4: Simplify right side
    780.02x = 522,126.46
  5. Step 5: Solve for x
    x = 522,126.46/780.02
  6. Step 6: Final answer
    x = 669.38

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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.