The process of the underground mining of the 1800

A system of air passages connected to the outside ventilated some mines and others used hand bellows or engine-powered fans. Early mines drained underground workings with tunnels or bucket bailers. Deep mining on the Comstock introduced large, steam-powered Cornish pumps.

Explanation:

angle a = 40.6°

step-by-step explanation:

for any right angle triangle we know the pythagoras theorem reveals

hypotenuse² = height²+base²

by this formula we will calculate the length of hypotenuse

h² = 6²+7²

⇒ h =√36+49 = √85 = 9.22

now from the given triangle sin a = height/ hypotenuse

                                                sin a = 6/9.22 = 0.651

therefore

so angle a = 40.6°

can we get more information?

explanation: