The measure of angle is 7 what is the measure of its complementary angle

What are the measures of ∠a, ∠b, ∠c and ∠d? explain how to find each of the angles. measure need asap

According to modern science, earth is about 4.5 billion years old and written human history extends back about 10,000 years. suppose the entire history of earth is represented with a 10-meter-long timeline, with the birth of earth on one end and today at the other end.

20 solve 2(4 x + 3) < 5 x + 21. a) { x | x < 9} b) { x | x > -5} c) { x | x > -9} d) { x | x < 5}