Okay, so the area of a triangle is A=bh/2. To find B, the equation would be 2A divided by h equals the base. That's just basic algebra, then you can plug in your numbers. So, 2(36) divided by 6 is 72/6 which is 12 so the base is 12 mm.
Pythagoras; a^2 + b^2 = c^2 So, (6.7)^2 + (5.5)^2 = 75.14 then square root to get, 8.668 (to 3 d.p) hope this helps!!
The answer is 6 because 12x6 is 72 and 16x3 is 48 and 48+24 is 72