What is a deltahedron?

Why is the product of the slopes of perpendicular lines always negative? How many square yards of concrete are in 1000 square feet with a 6 inch depth? Can you tessellate five sided regular polygons by themselves? All sides are equal and the diagonals are also equal and bisect at right angle what image? How do you get the radius if angle is 150 degrees and length of arc is 330 cm? What is the name of a quadrilateral with one pair of parallel lines two right angles and one acute angle? What is the formula of the intersection of two lines? Is a prop shaped like a airfoil? How many walls are there in a cube? What are the dimensions of a triangular prism with volume 3000 cm cubed? What is the perimeter of a octagon when the sides are 9mm and why? Can an isosceles trapezoid be a parallelogram and why? How do you form two squares by drawing five lines? What kind of topologies are good choices for highly available enterprise networks? What is the total area of a suitcase 20x30x12 in inches? What are faces on shapes? What is the angle between 5 and 8 on a clock? Why do all flags have the shape of rectangle? How much is a 650 square foot equivalent to square meter? How do you calculate the surface area and volume of rectangular prisms?