Roboguru

Perhatikan gambar di bawah ini. Diketahui   dan . Keliling  adalah … .

Pertanyaan

Perhatikan gambar di bawah ini.



Diketahui begin mathsize 14px style angle ACD equals angle BCD equals 30 degree end style  dan begin mathsize 14px style CD equals 10 square root of 3 space cm end style. Keliling begin mathsize 14px style triangle ABC end style adalah … begin mathsize 14px style cm end style.

  1. 30space 

  2. 40space 

  3. 50space 

  4. 60space 

Pembahasan Soal:

Diketahui: 

begin mathsize 14px style angle ACD equals angle BCD equals 30 degree end style
begin mathsize 14px style CD equals 10 square root of 3 space cm end style

Besar begin mathsize 14px style angle ACD equals angle BCD equals 30 degree end style, maka CD garis bagi segitiga ABC sehingga besar begin mathsize 14px style angle CDA equals angle CDB equals 90 º end style.

Perbandingan sisi-sisinya adalah begin mathsize 14px style BD space colon space CD space colon space BC equals AD space colon space CD space colon space AC equals 1 space colon space square root of 3 space colon space 2 end style.

begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row cell panjang space AC end cell equals BC row cell BC space colon space CD end cell equals cell 2 space colon space square root of 3 space end cell row cell BC space colon space 10 square root of 3 end cell equals cell 2 space colon space square root of 3 space end cell row cell square root of 3 BC end cell equals cell 2 cross times 10 square root of 3 space end cell row BC equals cell fraction numerator 20 square root of 3 over denominator square root of 3 end fraction end cell row BC equals cell space 20 space cm space space dan space AC equals 20 space cm end cell end table end style 

 

begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row cell Panjang space AD end cell equals cell BD space end cell row cell BD space colon space CD end cell equals cell 1 space colon space square root of 3 end cell row cell BD space colon space 10 square root of 3 end cell equals cell 1 space colon space square root of 3 space end cell row cell square root of 3 BD end cell equals cell 10 square root of 3 space end cell row BD equals cell fraction numerator 10 square root of 3 over denominator square root of 3 end fraction end cell row cell BD space end cell equals cell space 10 space cm space space dan space AD equals space 10 space cm end cell end table end style 

 

begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row cell panjang space AB end cell equals cell AD plus BD end cell row blank equals cell 10 plus 10 end cell row blank equals cell 20 space cm end cell end table end style 

Mencari keliling segitiga:

begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row cell keliling space segitiga end cell equals cell AB plus BC plus AC end cell row blank equals cell 20 plus 20 plus 20 end cell row blank equals cell 60 space cm end cell end table end style 

Jadi, keliling segitiga tersebut adalah begin mathsize 14px style 60 space cm end style.

Dengan demikian, jawaban yang tepat adalah D.

Pembahasan terverifikasi oleh Roboguru

Terakhir diupdate 12 Maret 2021

RUANGGURU HQ

Jl. Dr. Saharjo No.161, Manggarai Selatan, Tebet, Kota Jakarta Selatan, Daerah Khusus Ibukota Jakarta 12860

Coba GRATIS Aplikasi Ruangguru

Produk Ruangguru

Produk Lainnya

Hubungi Kami

Ikuti Kami

©2021 Ruangguru. All Rights Reserved