If the tree grows an additional 10 feet, what is the new angle of elevation from the point 25 feet from the base of the tree to the top of the tree? A)42.30
B)47.1°
C)49.8
D)54.6

Arley is building a model of a city map. in one part of the city, three roads form a right triangle, which harley draws as triangle abc, with the following measures: m∠b=90° and m∠a=30°. in his scale model, the hypotenuse of triangle abc, ac¯¯¯¯¯¯¯¯, has a length of 817−−√ cm. what is the value of a (the length of bc¯¯¯¯¯¯¯¯)?