Question

G

70°
H
100⁰
130
K
In the figure above, points G, J, K all lie on the
same line. What is the value of x?

Answer 1

x = 120

Explanation:

the sum of the 4 interior angles in quadrilateral GHIF = 360°

sum the angles and equate to 360° to find ∠ IJG

∠ IJG + ∠ G + ∠ H + ∠ I = 360°

∠ IJG + 70° + 100° + 130° = 360°

∠ IJG + 300° = 360° ( subtract 300° from both sides )

∠ IJG = 60°

∠ IJG and ∠ IJK are a linear pair and sum to 180°

sum the 2 angles and equate to 180

∠ IJG + ∠ IJK = 180 , that is

60 + x = 180 ( subtract 60 from both sides )

x = 120