Archimedes went to sleep beside a big rock. He wanted to get up at 8 a. M but the alarm clock was yet to be invented. He decided to sleep at the spot where the rock shadows should end when it's 8am so as to be awakened by direct sunlight

21.4 i did it already for s1

step-by-step explanation:

that is the sum

step-by-step explanation:

there are no other answers without knowing the variables values

12

step-by-step explanation:

a triangle's   full angle is 180 degrees so 180 - 156 = 24. 24/2=12

a 4/6 = 9/12   not proportional

step-by-step explanation:

to find which are not proportional, we can use cross products

if it is true, they are proportional.   if it is not true, they are not proportional.

a 4/6 = 9/12

4* 12 = 6*9

48 = 54

not this is not proportional  

b 2/3 = 12/18  

2* 18 = 3 * 12

36 = 36

this is proportional

c 5/4 = 10/8  

5*8 = 4*10

40 = 40

this is proportional

d 7/5 = 35/25

7*25 = 5 * 35

175 = 175

is proportional