Chris is making pancakes the recipe makes four servings. he wants to make enough for six servings. how much flower does he need.

basically get a shape

eg we will work with triangles,, add angles to the inside,, ensuring they add up to 180 (because angles in a triangle add up to 180)

now that we have the angles,, extend each side with a line to show the exterior angles.

we know that angles on a line add up to 180,, so to find the external angle,, we can use our internal angle

you would use:

[ 180- internal angle]

do this for all external angles

add all your answers together,, should equal to 180