Question

Using the defects method, which of these relationships represents the Law of Cosines if the measure of the included angle between the sides a and b of ∆ABC is more than 90°?

area of square c2 = -area of square a2 – area of square b2 + area of defect1 + area of defect2

area of square c2 = area of square a2 + area of square b2 + area of defect1 – area of defect2

area of square c2 = area of square a2 + area of square b2 – area of defect1 – area of defect2

area of square c2 = area of square a2 + area of square b2 + area of defect1+ area of defect2

area of square