What is the symbol of Hydrogen ?

Given a circle with measures of (c, d, and r) and a circle with measures of (c', d', and r'), what is d if c c' = 12 and d' = 0.50? a) 3 b) 6 c) 12 d) 24

Find an equation of the line perpendicular to the graph of 28x-7y=9 that passes through the point at (4,1)

In angle pqr find the measure of