a plank leans against the top a builfing at an angle of 30degrees to the horizontal. if the building is 12m high, what is the length of the plank

The center of the circumscribed circle lies on line segment and the longest side of the triangle is equal to the of the circle.

Jack did 3/5 of all problems on his weekend homework before sunday. on sunday he solved 1/3 of what was left and the last 4 problems. how many problems were assigned for the weekend?

An investment decreases in value by 30% in the first year and decreases by 40% in the second year. what is the percent decrease in percentage in the investment after two years