primary 6 chevron_right Maths chevron_right Singapore

Hi, need help with part (b) of the question.

I have managed to complete part (a) and worked out the area of the parallelogram to be 10 cm2 (by breaking it into two triangles of base 5 units, and height 1 unit)

For the parallelogram, I broke it into two triangles (base 5 units, height 1 unit) to get an area of 5cm2.

However, I am unsure how to go about calculating the area of the triangle.