Parallelogram Area

Consider the following parallelogram.

a. Calculate the value of x. And then, calculate the length of AB.
b. Calculate the area of the parallelogram.

Quoted from : Exercise No 3, page 305
(Marsigit. 2009. Mathematics I for Junior High School. Jakarta: Yudhistira.)

Solution:
a. Base on the properties of parallelogram, the opposite sides are equal and parallel to each other. So, we can calculate the value of x.
                    AB = CD
              4x - 15 = 2x + 3
              4x - 2x = 3 + 15
                     2x = 18
                       x = 9

After we calculate the value of x, we can determine the length of AB.

                     AB = 4x - 15
                     AB = 4.9 - 15
                     AB = 36 - 15
                     AB =  21

Hence, the value of x is 9 cm and the length of AB is 21 cm.


b. The base of parallelogram ABCD is AB = 21 cm.
The height of parallelogram ABCD is DE = 10 cm.
Therefore, we can calculate the area as:

                       L = base x height
                       L = AB x DE
                       L = 21 x 10
                       L = 210

Hence, the area of parallelogram ABCD is 210 cm²

From Traditional Teaching To Progressive Teaching

In Indonesia, many pupils think that mathematics as a dangerous lesson which threatens. This pupils assumption who think that mathematics as a difficult subject makes mathematics to less and less enthused. Thus, understanding of Indonesian pupils about mathematics is worse.

Based on these facts, it takes innovative teachers. Teachers should change the mathematics paradigm of pupils from the difficult lesson becomes easy lesson. These days, teachers are required to be able to teach in a progressive, not traditional teaching. This some steps for teaching that is suitable for today:

1. Teachers as facilitators.
Different with traditional teaching that makes the teacher as a center of learning, in progressive learning, teachers are positioned as a facilitator. Teachers are assisting and supervising pupils in learning. Hence, active learners is very necessary. Pupils will actively ask the teacher. So, for pupils who are less active, the teacher is required to motivate their pupils. This is where the encouragement of teachers can enhance pupils' desires.

2. The number of learning resources.
Learning resources can come from anywhere. Teacher isn’t always standing in front of the class. Pupils can acquire knowledge from his own experience. From his experience, it is hoped science would be more understandable.

3. Change obligation to the needs and awareness.
This is needed pupils who have false paradigm, so teacher should give an explanation to the pupils. In traditional teaching, giving homework is usually regarded as an obligation. In fact, homework is a need for pupils to study at home. Teachers are expected to change the attitude of pupils who are less aware of the importance of mathematics, be aware and take mathematics.

4. Change the value orientation into process orientation.
Give pupils an understanding of that value is only the size of the final result. The most important is the process of achieving the many benefits.

Well, that's a few steps that can be done by a mathematics teacher who want to succeed. So, slowly but surely, the pupils' understanding of mathematics will be increased.

How To Prepare I Myself as A Successfull Student of Mathematics

Success came to me when I consciously decided to success. As a student of mathematics education, I want to be not only a teacher but also a professional teacher. Here are some more ways to prepare a successfull student of mathematics education . We can begin with the basic. A student should have self development. Self development can make people be better. Self-development consists of somethings, that desire, vision, and responsibility. Every people should have it.
Then, the process of self-development depends on the motivation, attitude, knowledge, skills, and experience. For more details, we will explain one by one from the process.
1.Motivation
Motivation is a process that explains the intensity, direction, and persistence of an individual to achieve their goal. The highest motivation comes from religion. Islam as a religion that I embrace, teach us to always strive in earnest, working hard. Beside, we should worship with praying to God.
2.Attitude
Attitude is so important, it can be more important than physical characteristics and mental health in a personality. Attitudes reflect a person's personality. As an Indonesian who is identical with friendly, then we should be friendly with everyone. So, the attitude which should be shown as a student is positive attitudes that sync with the goals. Continuously that can make habits.
3.Knowledge
Knowledge in here can be defined as knowledge of life. That is about how to translate life and our lives. The aims to improve the quality of life.
4.Skills
Skills acquired outside formal education. Someone have proficient skills after repeated trial.
5.Experience
Experience is the best teacher. We must have many experiences, both good experiences and bad experiences. However, keep in mind, the experience is not only reserved to yourself but also others. If the experience that we have also distributed to others, it includes a high level.
Finally, it all depends on each individual. What are the steps will be selected. Success is a chance. Who can take a chance, they will achieve success. My goal is to become a professional teacher will come with my confidence. Keep spirit and do the best...