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Download a) See the second attach b) Two teams, one from tower A and
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a) See the second attach b) Two teams, one from tower A and another from tower B, start going straight from each location following the 2 black lines. They will meet at the source of smoke. c) Two ships A and B, on the sea could observe a light C at the shore. For ship A, the light tower is situated at the bearing of 45 degrees (clockwise from North), while for ship B, the light tower is situated 330 degrees (clockwise from North ). The student is wrong. We could measure an angle because it doesn’t matter how long the two rays are. We could put two points A and B on the two rays, and the angle doesn’t change. The angle between the 2 rays is same as the angle AOB, which it could be measured with a protractor. In geometry, two figures are congruent if they have the same shape and size, but are in different positions (for instance one may be rotated, flipped, or simply placed somewhere else). For example, two angles ABC and DFE, say, are "equal" if and only if there are exactly the same angle: that would mean that B and F are just different ways of referring to the same point and that A is on one of the rays FD or FE and C is on the other one. Two angles are "congruent" if and only if they have the same measure. Generally speaking, in mathematics, we use the term "equal" to mean "(possibly different) ways of referring to exactly the same object" and "congruent" to mean "have some specific property in common". Geometry, as developed in Euclid, was a systematic body of mathematical knowledge, built by deductive reasoning upon a foundation of three main pillars: (1) definitions of such things as points, lines, planes, angles, circles, and triangles; (2) the assumption of certain geometrical postulates regarded as true but perhaps not self-evident; and (3) the assumption of certain axioms or common notions which were taken to be self-evident truths. The body of Euclid's great work consists of a set of propositions or theorems, each derived systematically and logically from the definitions, axioms, and postulates of his foundation and from theorems already proved. See the second attach See the second attach We’ll use the fact that, in any right triangle, the sum of the other two angles =90 Therefore, since triangle ACB is right, then 55 + B = 90, so B = 35 degrees. Triangle CDB is also right, so x + B = 90. That makes x + 35 = 90. So we conclude that x = 35 degrees. The intersection between a plane and a cube could be: a) a square b) a rectangle c) a triangle The drawings are on the second attached It has 8 lateral faces. Each lateral face corresponds to a base side. The edges of the 2 base squares of the cube don’t look parallel as they do in a normal square on a piece of paper, because since the two base- squares of the 3- dimensional cube on a plane look like parallelograms. Compare those two pictures: Cube in a plane (bases are in black) Square in a plane (attached) A cylinder need not have circular bases, nor must a cylinder form a closed surface. If MNPQ is a curve in a plane (Fig. 1), and APB is a line that is not in the plane and that intersects the curve at a point P, then all lines parallel to AB and intersecting MNQ when taken together form a cylindrical surface. If the curve MNPQ is closed, the volume enclosed is a cylindrical solid. The term cylinder may refer to either the solid or the surface. The line APB, or any other line of the surface that is parallel to APB, is called a generatrix or element of the cylinder, and the curve MNPQ is called a directrix or base. In a closed cylinder, all the elements taken together form the lateral surface. A closed cylinder is circular, elliptical, triangular, and so on, according to whether its directrix is a circle, ellipse, or triangle. In a right cylinder, all elements are perpendicular to the directrix; in an oblique cylinder, the elements are not perpendicular to the directrix. In general, the volume of a closed cylinder between the base and a plane parallel to it is given by Bh, in which B is the area of the base and h is the perpendicular distance between the two parallel planes