Pls answer as fast as you can, no pressure.

Pavel is designing a restaurant and wants a unique dining area to add to the interest of the design. He thinks that an obtuse isosceles triangle would fulfill this requirement. He has two lengths of railing already in his possession—one that is 12 meters in length and one that is 22.8 meters in length. If he wants to keep his obtuse isosceles triangle design, which railing should he order a duplicate of to create his dining area. Explain.