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Finding the Fourth Proportional to 1,245.80, 1,719.21 and 686.28

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Solution

The fourth proportional to 1,245.80, 1,719.21 and 686.28 is: 947.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,245.80 : 1,719.21 = 686.28 : x
  2. Step 2: Convert to fraction form
    1,245.80/1,719.21 = 686.28/x
  3. Step 3: Cross multiply
    1,245.80x = 1,719.21 × 686.28
  4. Step 4: Simplify right side
    1,245.80x = 1,179,859.44
  5. Step 5: Solve for x
    x = 1,179,859.44/1,245.80
  6. Step 6: Final answer
    x = 947.07

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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.