19. On a straight line AB, take a point C. From C. draw a ray CX How many angles cze
you write from the figure so formed? Write all of them
14
20. Draw a rough sketch of a pentagon and draw its diagonals.
14
21. Which digits from 0 to 9 are symmetrical figure?
14
22. Draw a line segment of length 7.5 cm and construct its axis of symmetry.
14
23. What will be the length of the side of a regular pentagon whose perimeter is 85 m?
141
24. Pankaj and Karan started from a point at the same time. Pankaj took the route from A to
B. B to C, C to D and D to A. Karan walked through A to D, D to E, E to F and F to
A. If both of them have the same speed, who will reach at A earlier? The lengths of the
sides are shown in the diagram.
Originally, the terms “morning star” and “evening star” applied only to the brightest planet of all, Venus. Far more dazzling than any of the actual stars in the sky, Venus does not appear to twinkle, but instead glows with a steady, silvery light. The fact that Venus was a “wandering star” soon became obvious to ancient skywatchers, who noticed its motion relative to the background stars, going from the eastern sky in the morning to the western sky in the early evening. Nicolas Camille Flammarion, a noted French astronomer in the late 19th and early 20th century, referred to Venus as “The Shepherd’s Star.” I myself like to refer to Venus as the “night light of the sky.” So, it’s easier to understand the origin of the terms “evening star” and “morning star” if we only considered Venus.
Of course, Venus is not the only wandering “star” in the sky; there are four others that are also visible to the unaided eye (five, if you include Uranus, which is barely perceptible without any optical aid on dark, clear nights). The difference is that, with the possible exception of Jupiter and, on rare occasions, Mars, none of the others stands out in the same manner as Venus. Nonetheless, somewhere in the distant past, “morning star” and “evening star” became plural in order to account for the four other planets.