PLEASE HELP ME I'M SO CONFUSED I'VE BEEN TRYING TO FIGURE THIS OUT FOR LIKE 30 MINUTES SO PLEASE HELP I'LL GIVE BRAINLIEST TO THE CORRECT ANSWER Complete the following proof by filling in the blanks.
Given : ∠1 ≅ ∠4
Proven : ∠3 ≅ ∠4

How do i find the missing angle measure in a polygon

Which of the following vectors are orthogonal to (2,1)? check all that apply

Aspacecraft can attain a stable orbit 300 kilometers above earth if it reaches a velocity of 7.7 kilometers per second. the formula for a rocket's maximum velocity v in kilometers per second is vequalsminus0.0098tplusc ln upper r, where t is the firing time in seconds, c is the velocity of the exhaust in kilometers per second, and r is the ratio of the mass of the rocket filled with fuel to the mass of the rocket without fuel. find the velocity of a spacecraft whose booster rocket has a mass ratio of 20, an exhaust velocity of 2.1 km/s, and a firing time of 15 s. can the spacecraft achieve a stable orbit 300 km above earth?