The sum of the interior angles of a polygon is 20 right angles. How many sides does the polygon have?

Find the coordinates of the mid-point of x and y intercepts of the line 2y = 4x - 8

A hunter 1.6 m tall, views a bird on top of a tree at an angle of 45°. if the distance between the hunter and the tree is 10.4 m, find the height of the tree.

A solid hemisphere has a radius of 7 cm. Find the total surface area.

Find the value of a if the line 2y - ax + 4 = 0 is perpendicular to the line y + (x/4) - 7 = 0