Hello! answer: 45
Formula for triangles area: base × height ÷ 2
Formula for squares area: base × height
6 × 3 = 18 18 ÷ 2 = 9 since theres 4 identical triangles I'll just multiply by 4 to get all of those triangles area combined so... 9 × 4 = 36
now for the square thats just 3 × 3 and 3 × 3 = 9 now we just add these up for the total surface area so... 36 + 9 = 45 therefore the surface area is 45 HOPE THAT HELPS!