the element born has two stable isotopes. boron-10 has an atomic mass of 10.0129 and a percentage in nature of 19.78% the atomic mass of boron-11 is 11.0093 and its percentage in nature is 80.22% what is the average atomic mass for boron?

answer: 4 (:

step-by-step explanation:

first, you divide the triangle in two, tô form a retangle triangle. after, using pythagoream theorem:

18^2 = 14^2 + (x/2)^2

(x^2/4) + 196 = 324

x^2/4 = 324 - 196

x^2/4 = 128

x^2 = 512

x = √512

x = √2^9

x = 16√2 cm

i hope i you.

just keep asking questions until you have a better understanding.

step-by-step explanation:

for future students the answer is b

hope i

-lavira: )