77 degrees is the third angle
The answer to question 19 is 11 sequar root 2
and I don't know 20 sorry
Answers
Surface area is 964 cm2
Volume is 1872 cm3
Step by step
Using L=length, w=width, h= height
Surface area is found by adding the area of all 6 sides. Area is found by multiplying L x W.
8x18 = 144 x2 sides = 288
18x13 = 234 x2 sides = 468
8x13 = 104 x2 sides = 208
Total all sides = 964
Volume of a rectangle is found by multiplying L x W x H
13 x 18 x 8
Volume is 1872 cm3
