Item 11 Let ∠1, ∠2, ∠3, and ∠4 have the following relationships.

∠1 and ∠2 are vertical angles.

∠3 and ∠4 are right vertical angles.

∠3 is adjacent to both ∠1 and ∠2.

What is the sum of the measure of ∠4 and the measure of ∠1 minus the measure of ∠2?

answer: (-8,4) are the coordinates of a

step-by-step explanation:

let the side of square abcd is x .

thus the area of square abcd is .

now, by the diagram area of triangle ead= 1/2 × ea × ad = 1/2 × ea × x

( because ad is the side of square)

and, according to the question,

the areas of square abcd and right ead are equal.

⇒

⇒ea=2x

thus, ea: ab=2: 1

therefore, point a divides line segment eb into the ratio 2: 1.

⇒ by sectional formula coordinates of a are,

=

=

=(-8, 4)

thus the coordinates of a are (-8,4)