Earth’s surface area is 5.1 x 10 8 km 2 , its crust has an average thickness of 35 km and an average density of 2.8 g/cm 3 . The two rarest (non-radioactive) elements in the crust are ruthenium and rhodium, each with an abundance of 1.0 x 10 -4 g/metric ton crust. What is the total mass of these two elements in the earth’s crust? (1g = 1 x 10 -6 metric ton)

step-by-step explanation:

the first 5 right here the next 5 i will upload as separate question

a line is an defined derm because it

a)contains an infinite number of points b) can be used to create other geometric shapes c)describes something that does not have width or depth d) is a term that does not have a formal definition. a line is an undefined term because it: contains an infinite number of points.

207/8 is the right

hope it you

step-by-step explanation:

sin(7pi/6 - pi/3)  

= sin(7pi/6 - 2pi/6)  

= sin(5pi/6)  

= sin(pi - pi/6)  

= sin(pi/6)  

= 1/2  

sin 7pi/6 - sin pi/3  

= sin (pi + pi/6) - sin pi/3  

= -sin pi/6 - sin pi/3  

= -1/2 - sqrt(3)/2  

= -(1+sqrt(3))2