1. Consider the region bounded by the graphs of x = yz and x = 9. Find the volume of the solid that has this region as its base if every cross section by a plane perpendicular to the x-axis has the shape of an equilateral triangle. (Hint: Precalc review...if one side of an equilateral triangle is s, then the area of the triangle is 3-$2). 2. The base of a solid is a region bounded by the curve $2 + y 82 + 42 = 1 (an ellipse with the major and minor axes of lengths 16 and 8 respectively). Find the volume of the solid if every cross section by a plane perpendicular to the major axis (x-axis) has the shape of an isosceles triangle with height equal to - the length of the base.3. The base of a solid is a right triangle whose base side has length a and whose perpendicular side has length %a. Find the volume of the solid if cross sections perpendicularto the base of the triangle are semicircles. 4. A solid has as its base the region bounded by the curves y = -?_r2 +2 and y = 2 +1. Find the volume of the solid ifevery cross section of a plane perpendicular to the x-axls Is a trapezoid with lower base in the xy-plane, upper base equal to -2L the length of the lower base, and height equal to 2 times the length of the lower base. Brain Teaser: A tetrahedron has three mutually perpendicular faces and three mutually perpendicular edges of lengths 2, 3, and 4 cm, respectively. Find its volume