Corrected Question
Quadrilateral QRST is inscribed in circle W as shown below. The measure of ∠QRS is 12 degrees less than three times the measure of ∠QTS and
mRQT=mRST .
(a)Determine the measure of Angle QTS .
(b)What is the common measure of angles RQT and RST ?
Answer:
(a)48 degrees
(b)90 degrees
Explanation:
Theorem: Opposite angles of a cyclic quadrilateral are supplementary.
(a)
Let the measure of ∠QTS=x
Therefore: m∠QRS=3x-12
∠QTS and ∠QRS are opposite angles of a cyclic quadrilateral. By the theorem above:
x+3x-12=180
4x=180+12
4x=192
x=48 degrees
The measure of angle QTS is 48 degrees.
(b)Since mRQT=mRST
mRQT and mRST are opposite angles of a cyclic quadrilateral
Therefore:
mRQT+mRST=180 degrees
2mRQT=180
mRQT=90 degrees
Therefore, the common measure of RQT and RST is 90 degrees.