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Finding the Fourth Proportional to 719.11, 990.30 and 686.31

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Solution

The fourth proportional to 719.11, 990.30 and 686.31 is: 945.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    719.11 : 990.30 = 686.31 : x
  2. Step 2: Convert to fraction form
    719.11/990.30 = 686.31/x
  3. Step 3: Cross multiply
    719.11x = 990.30 × 686.31
  4. Step 4: Simplify right side
    719.11x = 679,652.79
  5. Step 5: Solve for x
    x = 679,652.79/719.11
  6. Step 6: Final answer
    x = 945.13

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1.5x scale

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.