Question

Triangle ABC has vertices A( -3, 5) B ( 6, 9) and C ( -4, - 12) in the coordinate plane. The triangle is reflected over the x- axis and then rotated 90˚ about the origin to form triangle A''B''C''. What are the coordinates of triangle A''B''C''.

Answer 1

The coordinates of triangle A"B"C" will become

A( 5,-3 ) B( 9,6 ) C( -12 ,-4 )

Explanation:

Original vertices of triangle ABC are ;

A ( -3, 5 ) B( 6, 9 ) C ( -4, -12 )

after reflection over x-axis

A( -3,-5 ) B( 6, -9 ) C( -4,12 )

when the triangle is rotated

x coordinates becomes -y while y coordinates becomes x

The coordinates of triangle A"B"C" will become

A( 5,-3 ) B( 9,6 ) C( -12 ,-4 )