Virginia SOL 7.MG.3.d
The Standard
Given a diagram, determine an unknown side length in a quadrilateral using properties of quadrilaterals.
Virginia Standards of Learning for Mathematics · The student will compare and contrast quadrilaterals based on their properties and determine unknown side lengths and angle measures of quadrilaterals.
Teacher's field guide
What This Standard Means
What Students Need to Do
- Students use the properties of parallelograms, rectangles, rhombi, squares, and other quadrilaterals to relate side lengths. They write an equation when lengths include variables, solve it, and find the requested measure.
What Mastery Looks Like
- Students identify the side relationship shown by the shape, labels, and markings. They write and solve an equation, substitute the value, and report the side length with units.
Common Misconceptions
- Students may assume every quadrilateral has congruent opposite sides. They may confuse parallel arrow marks with congruent side marks, or solve for x but forget to find the requested length.
How to Assess It
- Exit ticket: In parallelogram ABCD, AB = 3x + 2 cm and CD = 20 cm. Find x and AB, then name the property used.
Lesson moves
Ways to Teach It
Build quadrilaterals with craft sticks, measure each side, and record which side relationships remain true for each named shape.
Ask students to respond: A classmate says every quadrilateral has two pairs of congruent sides; give a counterexample and explain.
Match diagram cards with equation cards, then solve each match and check the answer against the side labels.
Use a rectangular window diagram with one labeled side to calculate the missing length of trim on the opposite side.
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Printable 7.MG.3.d Worksheet
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Related Standards
- 4.MG.5.c
Identify and describe parallel, intersecting, perpendicular, and congruent sides in quadrilaterals.
- 7.MG.3.c
Given a diagram, determine an unknown angle measure in a quadrilateral, using properties of quadrilaterals.
- 7.MG.2.f
Solve a proportion to determine a missing side length of similar quadrilaterals or triangles.
- 7.MG.3
The student will compare and contrast quadrilaterals based on their properties and determine unknown side lengths and angle measures of quadrilaterals.
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