Five-Minute Check (over Lesson 11–3)
Then/Now
New Vocabulary
Key Concept: Angles of a Quadrilateral
Example 1: Find Angle Measures
Example 2: Real-World Example: Classify Quadrilaterals
Over Lesson 11–3
Choose the figure after a 180° clockwise rotation about point S.
A.
B.
C.
D.
Over Lesson 11–3
Choose the figure after a 270° clockwise rotation about point A.
A.
B.
C.
D.
Over Lesson 11–3
Which figure does not have rotational symmetry?
A.
B.
C.
D.
Over Lesson 11–3
A. A'(0, 3), B'(–6, 5), C'(1, 5)
B. A'(0, 3), B'(5, 1), C'(–2, 1)
C. A'(0, 3), B'(6, 5), C'(2, 4)
D. A'(0, 3), B'(–5, 1), C'(2, 1)
A triangle has vertices A(0, 3), B(–2, –3), and C(–2, 4). If the triangle is rotated clockwise 90° about point A, what are the new coordinates of the triangle?
You found missing angle measures of a triangle. (Lesson 10–3)
• Find missing angle measures of a quadrilateral.
• Classify quadrilaterals.
• quadrilateral
Find Angle Measures
ALGEBRA Find the value of x in the quadrilateral. Then find each missing angle measure.
The sum of the measures of the angles is 360°.
Let mQ, mR, mS, and mT represent the measures of the angles.
Find Angle Measures
mQ + mR + mS + mT = 360 Angles of a quadrilateral
75 + 4x + 110 + x = 360Substitution
5x + 185 = 360 Combine like terms.
5x + 185 – 185 = 360 – 185 Subtract 185 from each
side.
5x = 175 Simplify.
x = 35 Divide each side by 5.Answer: So, mT = 35° and mR = 4(35) or 140°.
A. x = 4; mA = 4° and mC = 16°
B. x = 5; mA = 5° and mC = 20°
C. x = 40; mA = 40° and mC = 160°
D. x = 104; mA = 104° and mC = 416°
Find the value of x. Then find each missing angle measure.
Classify Quadrilaterals
Answer: parallelogram
Classify the quadrilateral shown using the name that best describes it.
The quadrilateral has both pairs of opposite sides parallel and congruent.
A. square
B. rectangle
C. rhombus and rectangle
D. parallelogram and square
QUILT PATTERN The figure shows a pattern for the border of a quilt. Classify the quadrilaterals used to form the flower and the leaves using the name that best describes them.