Step-by-step explanation: A transformation is when we change the position or size of a given figure.
In part a, notice that we can flip the triangle on the left over the following line to the position of the triangle on the right. When we flip a figure over a line to create a mirror image, the new image is called a reflection. Therefore, the transformation shown in part a is called a reflection.
In part b, notice that we can turn the triangle on the top to the position of the triangle on the bottom. When we turn a figure to a new position, it's called a rotation. Therefore, the transformation in part b is a rotation.
In part c, notice that we can slide the triangle on the left to the position of the triangle on the right. When we slide a figure to a new position, it's called a translation. Therefore, the transformation in part c is a translation.
In part d, notice that the triangle on the left has been reduced in size to form the triangle on the right. When we reduce or increase the dimensions of a figure while maintaining its shape, the new image is called a dilation. Therefore, the transformation in part d is a dilation.