Mathematics for IGCSE & O level - Angles (Section 4 - No. 3)
If a quadrilateral has angles of 70°, 110°, and 90°, what is the value of the fourth angle?
70°
90°
110°
360°
설명
Sum of angles in a quadrilateral is 360°. The fourth angle = 360° - 70° - 110° - 90° = 90°.