Garis dan Sudut (2) | Satuan Sudut | Matematika Kelas 7

Summary

This video tutorial teaches 7th-grade mathematics, focusing on the topic of angles and their units of measurement. It explains three systems: sexagesimal, centesimal, and radian. The video covers the conversion between degrees, minutes, and seconds, with clear examples such as converting 9 degrees to minutes, and 12 minutes to seconds. It also discusses operations like multiplication, addition, and subtraction of these units. The video provides various examples, including how to solve problems involving different units, and emphasizes the importance of understanding these conversions for geometric calculations.

Takeaways

• 😀 The video discusses three units of angular measurement: sexagesimal, centesimal, and radian.
• 😀 The sexagesimal system includes degrees, minutes, and seconds, where 1 degree = 60 minutes and 1 minute = 60 seconds.
• 😀 The video focuses on explaining conversions between degrees, minutes, and seconds in the sexagesimal system.
• 😀 To convert from degrees to minutes, you multiply by 60, and to convert from minutes to seconds, you multiply by 60.
• 😀 Example 1: 9° = 540 minutes (9 × 60 = 540).
• 😀 Example 2: 12 minutes = 720 seconds (12 × 60 = 720).
• 😀 Example 3: 15° = 54,000 seconds (15 × 3600 = 54,000).
• 😀 Example 4: 45 minutes = 3/4 degrees (45 ÷ 60 = 3/4).
• 😀 Example 5: 75 seconds = 1 1/4 minutes (75 ÷ 60 = 1 1/4).
• 😀 The script also explains how to perform operations (multiplication, addition, subtraction) with these angular units, such as converting fractions and mixed fractions into degrees, minutes, and seconds.

Q & A

What are the three types of angle units discussed in the video?

The three types of angle units discussed are: Sexagesimal system, Centisimal system, and Radian system.

What is the relationship between degrees, minutes, and seconds in the Sexagesimal system?

In the Sexagesimal system, 1 degree equals 60 minutes, and 1 minute equals 60 seconds. Thus, 1 degree = 3600 seconds.

How is 9 degrees converted into minutes?

To convert 9 degrees into minutes, multiply 9 by 60, resulting in 540 minutes.

How do you convert 12 minutes into seconds?

To convert 12 minutes into seconds, multiply 12 by 60, resulting in 720 seconds.

What is the result of converting 15 degrees into seconds?

To convert 15 degrees into seconds, multiply 15 by 3600, which equals 54000 seconds.

How is 45 minutes converted into degrees?

To convert 45 minutes into degrees, divide 45 by 60, which equals 3/4 degrees.

What is the result of converting 75 seconds into minutes?

To convert 75 seconds into minutes, divide 75 by 60, which simplifies to 1 1/4 minutes.

What is the process to multiply 1/3 by 17 degrees?

To multiply 1/3 by 17 degrees, simply multiply 1/3 by 17, resulting in 17/3 degrees. This is then converted into a mixed fraction, 5 2/3 degrees, and further into 5 degrees and 40 minutes.

How do you add 40° 32 minutes 35 seconds and 26° 34 minutes 58 seconds?

First, add the seconds, then the minutes, and finally the degrees. After the addition, convert any overflow (60 seconds or minutes) into the appropriate unit. The result is 67° 7 minutes 33 seconds.

How is subtraction of angle units performed, for example, subtracting 37° 18 minutes 41 seconds from 55° 43 minutes 52 seconds?

To subtract angle units, handle seconds, minutes, and degrees separately. If a unit is smaller than the one being subtracted, borrow from the next unit. For this example, the result is 18° 25 minutes 11 seconds.