Please help 1. rubidium has two isotopes, 72.2% rubidium-85, and 27.8% rubidium-87. Calculate the average atomic mass of rubidium. 2. Bromine also has two isotopes: 50.7% is bromine-79 and 49.3% is bromine-81. Can you estimate the average atomic mass of bromine without using a calculator? 3. What is the average atomic mass of fluorine, whose only naturally occurring isotopes has an atomic mass of 19?

pentagon

step-by-step explanation:

the coordinates   a(5, -2), b(3,-1),c(-4,-4) d(-3,8) and e(-1,4) forms the vertices of the polygon when they are connected in order.

in order to classify that which polygon is it with the given coordinates, first count the number of vertices and then count the number of sides it can make with these vertices.

since, the given coordinates have five vertices, therefore, it will make five sides. moreover, pentagon is regular in nature therefore it will be convex.

now, a polygon with five sides is known as pentagon, therefore, the given polygon is the pentagon.

.24

step-by-step explanation:

the probability is   .24

the first player had the highest probability of getting a silver marble

the game could be made fair by adding back the marble that was drawn after each draw

something over 10 so ? /10

step-by-step explanation: