Hello :
tanA = sinA/cosA
cosA = sinA /tanA
cosA =(4/5)/(4/3)
cosA=3/5
An inertial reference frame is a frame of reference in which a body remains at rest OR moves with a constant LINEAR velocity. Answer choices A, C, and D are moving linearly at a constant rate and are all inertial frames of reference. Answer choice E is motionless, and is therefor an inertial frame of reference. Answer choice B is rotating at a constant rate. Rotation is not an inertial frame of reference.
Therefor, the answer is B.
Answer:
Step-by-step explanation:
This study investigated three mathematics teachers' construction process of geometric structures using compass and straightedge. The teacher-student-tool interaction was analysed. The study consists of the use of a compass and straightedge by the teachers, the ideas of the teachers about their use, and the observations regarding the learning process during the construction of the geometric structures. A semi-structured interview was conducted with the teachers about the importance of the use of a compass and straightedge to construct geometric structures. It was found that teachers taught compass and straightedge constructions in a rote manner where learning is little more than steps in a process. The study concludes with some suggestions for the use of a compass and straightedge in mathematics classes based on the research results. SUMMARY Purpose and significance: For more than 2,000 years, the way in which geometric structures could be constructed with the help of compasses and straightedges has caught the attention of mathematicians. Nowadays, mathematics curriculums place an emphasis on the use of the compass and straightedge. The compass and straightedge is more important in constructing geometric structures than other drawing tools such as rulers and protractors. Because steps taken with a compass and straightedge cannot be seen at first glance and this situation become a problem for students. However, 'doing compass and straightedge construction early in the course helps students to understand properties of figures'
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Y+Y+30=90
2Y=60 /:2
Y=30
PNQ=30°
QNO=30+30=60°
