The problem asks which rotation about the origin transforms the point $A(2, -6)$ to the point $A'(-6, -2)$. The possible rotations are: (a) $-180^\circ$, (b) $-90^\circ$, (c) $90^\circ$, and (d) $180^\circ$.

GeometryRotationsCoordinate GeometryTransformations
2025/4/28

1. Problem Description

The problem asks which rotation about the origin transforms the point A(2,6)A(2, -6) to the point A(6,2)A'(-6, -2). The possible rotations are: (a) 180-180^\circ, (b) 90-90^\circ, (c) 9090^\circ, and (d) 180180^\circ.

2. Solution Steps

A rotation of θ\theta about the origin transforms a point (x,y)(x, y) to (x,y)(x', y'), where:
x=xcosθysinθx' = x \cos \theta - y \sin \theta
y=xsinθ+ycosθy' = x \sin \theta + y \cos \theta
Let's check each option:
(a) θ=180\theta = -180^\circ: cos(180)=1\cos(-180^\circ) = -1, sin(180)=0\sin(-180^\circ) = 0.
x=(2)(1)(6)(0)=2x' = (2)(-1) - (-6)(0) = -2
y=(2)(0)+(6)(1)=6y' = (2)(0) + (-6)(-1) = 6
This gives (2,6)(-2, 6), which is not (6,2)(-6, -2).
(b) θ=90\theta = -90^\circ: cos(90)=0\cos(-90^\circ) = 0, sin(90)=1\sin(-90^\circ) = -1.
x=(2)(0)(6)(1)=6x' = (2)(0) - (-6)(-1) = -6
y=(2)(1)+(6)(0)=2y' = (2)(-1) + (-6)(0) = -2
This gives (6,2)(-6, -2), which matches the desired point.
(c) θ=90\theta = 90^\circ: cos(90)=0\cos(90^\circ) = 0, sin(90)=1\sin(90^\circ) = 1.
x=(2)(0)(6)(1)=6x' = (2)(0) - (-6)(1) = 6
y=(2)(1)+(6)(0)=2y' = (2)(1) + (-6)(0) = 2
This gives (6,2)(6, 2), which is not (6,2)(-6, -2).
(d) θ=180\theta = 180^\circ: cos(180)=1\cos(180^\circ) = -1, sin(180)=0\sin(180^\circ) = 0.
x=(2)(1)(6)(0)=2x' = (2)(-1) - (-6)(0) = -2
y=(2)(0)+(6)(1)=6y' = (2)(0) + (-6)(-1) = 6
This gives (2,6)(-2, 6), which is not (6,2)(-6, -2).
Therefore, the rotation that transforms A(2,6)A(2, -6) to A(6,2)A'(-6, -2) is a rotation of 90-90^\circ about the origin.

3. Final Answer

(b) R (O, -90°)

Related problems in "Geometry"

Point P moves on the circle $(x-6)^2 + y^2 = 9$. Find the locus of point Q which divides the line se...

LocusCirclesCoordinate Geometry
2025/6/12

We are given three points $A(5, 2)$, $B(-1, 0)$, and $C(3, -2)$. (1) We need to find the equation of...

CircleCircumcircleEquation of a CircleCoordinate GeometryCircumcenterRadius
2025/6/12

The problem consists of two parts: (a) A window is in the shape of a semi-circle with radius 70 cm. ...

CircleSemi-circlePerimeterBase ConversionNumber Systems
2025/6/11

The problem asks us to find the volume of a cylindrical litter bin in m³ to 2 decimal places (part a...

VolumeCylinderUnits ConversionProblem Solving
2025/6/10

We are given a triangle $ABC$ with $AB = 6$, $AC = 3$, and $\angle BAC = 120^\circ$. $AD$ is an angl...

TriangleAngle BisectorTrigonometryArea CalculationInradius
2025/6/10

The problem asks to find the values for I, JK, L, M, N, O, PQ, R, S, T, U, V, and W, based on the gi...

Triangle AreaInradiusGeometric Proofs
2025/6/10

In triangle $ABC$, $AB = 6$, $AC = 3$, and $\angle BAC = 120^{\circ}$. $D$ is the intersection of th...

TriangleLaw of CosinesAngle Bisector TheoremExternal Angle Bisector TheoremLength of SidesRatio
2025/6/10

A hunter on top of a tree sees an antelope at an angle of depression of $30^{\circ}$. The height of ...

TrigonometryRight TrianglesAngle of DepressionPythagorean Theorem
2025/6/10

A straight line passes through the points $(3, -2)$ and $(4, 5)$ and intersects the y-axis at $-23$....

Linear EquationsSlopeY-interceptCoordinate Geometry
2025/6/10

The problem states that the size of each interior angle of a regular polygon is $135^\circ$. We need...

PolygonsRegular PolygonsInterior AnglesExterior AnglesRotational Symmetry
2025/6/9