Question

How do you do this because it's complicated

Answer 1

FAM U JUST NEED TO BELIEVE JUST BELIEVE USE THE POWER OF DANK MEMES THEN YOUR DREAMS WONT BE DREAMS

Answer 2

The triangle is a 45-45-90 triangle whose legs are equal Therefore  the other leg , which is also the side of the regular hexagon = 12 cm 
The area of the whiole figure = area of triangle + area of the hexagon
                                              =   1/2 * 12*12      + 6 *  1/2 * 12 * 6 sqrt3