Step 1) Create a new empty sketch and draw 2 lines that meet. The lines should be 3 and 4 in length and should connect at one point. They should be dimensioend to be 3 and 5 but they will be blue and that is ok

Step 3) Dimension the angle to 45 degrees. Link . You shoul dhave something liek this (your orientation/angle might be different)

Step 4) connect the vertices to make a triangle. Picture:

Step 5)

Step 6) Add a chamfer. Take a screenshot and submit on classrom