Question

Besar sudut ABC adalah
a. 60 derajat
b. 65 derajat
c. 70 derajat
d. 80 derajat​

Answer 1

• Nilai x

4x - 5° = 180° - (3x + 30°) + 55°

4x - 5° = 180° - 3x - 30° + 55°

4x + 3x = 180° - 30° + 55° + 5°

7x = 210°

x = 30°

• Besar sudut ABC

= 180° - (4x - 5°)

= 180° - (4(30°) - 5°)

= 180° - (120° - 5°)

= 180° - 115°

= 65° (B.)

Answer 2

Menentukan Nilai X Nya Terlebih Dahulu ^^

( 4x - 5 ) + ( 3x + 30 ) = 180° + 55°

4x + 3x - 5 + 30 = 235°

7x + 25° = 235°

7x = 235° - 25°

7x = 210

x = 210/7

x = 30°

____________________

Menentukan Sudut ABC

Sudut ABC + ( 4x + 5 ) = 180°

Sudut ABC = 180 - ( 4x - 5 )

Sudut ABC = 180 - ( 4(30) - 5 )

Sudut ABC = 180 - ( 120 - 5 )

Sudut ABC = 180 - ( 115 )

Sudut ABC = 65° ( B )