I cant draw triangles with different sides lengths

Hi I need to draw a triangle with different sides lenght but I dont know ho can some one please help me??

Any closed polyline with three sides will be a triangle. Use the polyline tool, click the start point, enter a length to limit the first side to what you want, click the second point, enter a length, then close… --Mitch

If you have tree side lengths, A, B & C, draw a line with A as length. Then at each end of the line draw a circle with B and C as the radius. Where the circles cross you have your solution. If the line was horizontal you have two triangles, one pointing up, another pointing down.

Thanks that was very helpful. My workmate also suggested that you only need to sides lengths and the angle between them and I used the computer angle generator. Just in case some has the same issues.