Side Side Side
Use the Angle tool to measure all the corresponding angles to make sure that they are the same size.
Side Angle Side
Drag the purple line to both triangles to make sure that the same line fits both triangles and therefore that the 3rd side of each triangle is the same length.
Angle Side Angle
Use the the Line tool to complete the triangles and then use the Distance or Length tool to measure the 2 pairs of corresponding sides to make sure they are the same length.
Right-angle Hypotenuse Side
Use the Line tool to create the missing sides and then use the Distance or Length tool to measure these sides to ensure that they are the same length.