Resistance is the opposition
to current flow in a conductor, measured in Ohms. The symbol is R. 
A good conductor such as
copper has a low resistance. A good insulator such as mica has a high
resistance. 
Ohms law is named after Georg Simon Ohm
who presented his laws back in 1827. In his honour the unit of electrical
resistance was named the 'ohm' . Ohms law relates voltage,
current and resistance. 
Power is the rate that energy
is used or dissipated, measured in Watts. The symbol is P. 
Use Ohms law to find a value  cover ONE symbol in the triangle
to solve the formula

Volts (V), Amps (I) & Ohms (R) 
Watts (P), Volts (V) & Amps (I) 

