Question

Figure ABCD is a rectangle with point A (−2, 5). What rule would rotate the figure 90° clockwise?

Answer 1

Explanation:

The general rule for rotation of an object 90 degrees is (x, y) to (-y, x)

so for point A(-2,5), A' will be (5,2)

to find the new

X=xcos(θ)+ysin(θ)

X=-2(cos90)+5sin90 ( cos90=0, sin 90=1)

X=5

to find the new

Y=−xsin(θ)+ycos(θ)

Y=-(-2)sin90+5cos90

Y=2

Answer 2

(5,2)

Explanation:

The 90° clockwise rule (for around the origin) is:
`(x,y)\rightarrow(y,-x)`

Apply the rule to point A:

`\left \{ {(-2,5)\rightarrow(5,2)} \atop {(x,y)\rightarrow(y,-x)}} \right.`

A' should be (5,2).