Texas Math Models

Try “number line” or “4.5D”

Work backwards to find a missing side

12 + 7 + 12 + 7 = 38 units G4

the perimeter is given; a side is missing66??P = 261212??P = 3826 − 12 = 1414 ÷ 2 = 738 − 24 = 1414 ÷ 2 = 7take off the two sides you know, then share what is left between the other two

How this one works

How

take the known sides off the perimeter, then split what’s left.

Best when

you get the perimeter, not every side.

seen one of these on a test? See it on a real question: TEKS 3.7B, perimeter, and a missing side, or TEKS 4.5D, perimeter and area of rectangles.

The same problem, other ways