INVESTIGATION ABOUT TRANSLATIONS
Given the triangle of vertices A−3 , 2 , B 2 ,1 and C 0 , 4 (blue)
a) Translate it by vector u =1,3 . Calculate the coordinates of the new vertices A´, B´and C´.(red)
b) Translate the triangle A´B´C´by vector v = 2,−7 to get triangle A´´B´´C´´ (black). How can you
get this last triangle from the original one? Explain.
c) Calculate the length sides of these triangles. How are these figures? Can you calculate the area of each
triangle? Look on Internet for the Heron´s formula.
EXERCISES ABOUT ROTATIONS AND REFLECTIONS
1.- a) Draw the triangle vertices A0,0 ; B 2,−1 and C 5,3 . Use a protractor to rotate the
triangle at an angle of 72º about the origin of coordinates.
b) Rotate the same triangle four more times,
each of them at an angle of 72º. What
happens?
2.- Point A 4,3 has been transformed by a rotation to a congruent point A ´ −2,5 and point
B 3,5 it´s been transformed to B ´ −4,2 . How do you find the centre of the rotation? How
much does the rotation´s angle measure?