STEP 1: Use the ruler to draw a straight horizontal line, draw a diagonal line from the end of the horizontal line... Image caption, ...and draw another diagonal line to join the points and mark the ...

A triangle is a polygon. It is a closed 3-sided shape made up of straight lines. The ‘tri-’ part of the word triangle means three. A triangle has 3 sides and 3 angles. Interior angles are the angles ...