Mathematics and Society - OS X Lion Server

(PAGE: 2.)f. Repeat steps b through d to measure the angular size of the circle at variousdistances from the chalkboard.How is the angular size of an object affected by its distance from theobserver? For additional practice measure the angular sizes of severalround objects in the room.3. Similar triangles are used to determinethe actual size of an object when itsangular size is known. To help youidentify the similar triangles:a. Draw and cut out a 2 cm and a 4 cmdisk. Mark the center of each disk.b. Draw a 10° angle.c. Place both disks in the 10° angle sothat the disks just touch the sidesof the angle. Measure the distancefrom ~he center of each disk to thevertex of the angle. The ratio ofthe distances is about 2:l--the sameas the ratio of the diameters.BOil-l D15K.S HA\JETHE: SAME" APPARENTOR ANGULAR SIz.eoo'?s~ ~~.~~Q:$==o\f'. VoTRIAtIlGLE: RST ISSIMILAR TO TRIAlI.lGLE:. RUV.RB: RA =UV:STd. Repeat c for a 20° angle.IDEA FROM:Charting the Universe, Book 1. The University of Illinois Astronomy Program99