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Finding the Fourth Proportional to 719.06, 990.78 and 485.78

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Solution

The fourth proportional to 719.06, 990.78 and 485.78 is: 669.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    719.06 : 990.78 = 485.78 : x
  2. Step 2: Convert to fraction form
    719.06/990.78 = 485.78/x
  3. Step 3: Cross multiply
    719.06x = 990.78 × 485.78
  4. Step 4: Simplify right side
    719.06x = 481,301.11
  5. Step 5: Solve for x
    x = 481,301.11/719.06
  6. Step 6: Final answer
    x = 669.35

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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.