1.
The edge lengths of a triangle are inversely proportional to 2,3 and 4.
The actual proportions of the lengths are then
12(1/2:1/3:1/4)=6:4:3
The longest side
= 39* (6/(6+4+3)
= 39*6/13
=18
2. 63 breads : 35 kg flour
is the same as
54 breads : x kg flour
Cross multiply and get
x=54*35/63=30
30 kg of flour are needed to make 54 breads.
4y - 8 - 2y + 5 = 0
2y - 3 = 0
2y = 3
y = 3/2
156°
D is a 24° angle, and is placed in a 90° angle, so 90-24=66
C is a right angle, so 90+66=156°
Hope this helped!