Key takeaway: This grade 7 constructing test answer key lays out each solution next to the points it earns, from the inequality check to the final sentence. Graders can credit a correct inequality or angle sum even when a later step slips.
Each note names the condition that decides the answer, such as a failed inequality or a non-included angle. Accept any clear explanation, and look for the word strictly when a sum equals the longest side. Brief notes flag the usual errors.
This answer key for the constructing triangles test shows a worked solution for every question, together with a scoring guide that explains how the 20 points are awarded. Give partial credit for a correct inequality or angle sum even when a later step has an arithmetic slip.
Grade 7 Constructing Test Answer Key: questions 1–5
1. Triangle inequality (3 points)
- \(6+9=15>14\): yes
- \(5+7=12\), not greater than 12: no
- \(8+8=16>15\): yes
Scoring: 1 point per part. Award the point for the correct yes/no answer supported by the correct sum.
2. Third side (2 points)
The third side \(x\) must satisfy \(8+11=19>x\) and \(x>11-8=3\).
- 4 in.
- 18 in.
Scoring: 1 point per part. Answers of 3 in. or 19 in. earn no point because those lengths fail the inequality.
3. Angle measures (2 points)
- \(48+77=125\) and \(180-125=55\): \(55^{\circ}\)
- \(38+64+79=181\), which is not \(180\). No.
Scoring: 1 point per part. Part (b) needs the sum 181 or a statement that the sum is not \(180^{\circ}\).
4. Protractor angle (2 points)
- The side crosses the outer scale at 115: \(115^{\circ}\)
- The other two angles add up to \(180-115=65\), and each must be greater than 0. The largest whole number is \(64^{\circ}\).
Scoring: 1 point per part.
5. How many triangles? (4 points)
- \(5+6=11>7\): exactly one
- \(8>3+4=7\): no triangle
- The angles add up to \(180^{\circ}\) and no side is given: more than one (many sizes)
- Two sides and the angle between them: exactly one
Scoring: 1 point per part.
Grade 7 Constructing Test Answer Key: questions 6–8
6. Side-side-angle (2 points)
He is not correct. The given angle is not between the given sides. A 6 cm compass arc centered at C crosses the other ray at two points, so a second triangle exists with AB about 5.3 cm instead of about 8.5 cm.
Scoring: 1 point for saying he is not correct. 1 point for explaining that two triangles fit (the arc crosses the ray twice).
7. Straws (3 points)
- \(11>4+6=10\). No.
- The new length \(x\) needs \(4+6=10>x\) and \(x>6-4=2\). Smallest 3 in., largest 9 in.
Scoring: 1 point for part (a). Part (b): 1 point for each correct length.
8. Construction steps (2 points)
- Draw segment AB, 7 cm long, with the ruler.
- Place the protractor center on A with its 0 line along AB and mark \(50^{\circ}\).
- Draw a ray from A through the mark and measure 5 cm along it to place C.
- Join B to C.
Scoring: 1 point for drawing AB and the \(50^{\circ}\) angle at A in the right order. 1 point for placing C at 5 cm and joining B to C.
Scoring summary
20 points: add the points of every question of this grade 7 constructing test answer key.
Which answers open the triangle test?
The set 6, 9, 14 works because 6 plus 9 is 15, which beats 14. The set 5, 7, 12 fails because the sum only equals 12. For sides of 8 and 11 inches, the smallest third side is 4 and the largest is 18.
How does a grade 7 constructing test answer key score the counting item?
This item is worth four points, one for each set of measurements. A set with three sides that satisfy the inequality gives exactly one triangle. Two sides with the included angle also give one. A set with a side-side-angle arrangement may give two, one, or none, so check the conditions.
How should the side-side-angle claim be graded?
Jamal draws an angle of 40 degrees with sides of 9 and 6 centimeters, and the angle is not between the sides. Full credit goes to a student who explains that the arc of 6 can cross the ray in two places. A student who says there is only one triangle earns the setup point at most.
What partial credit works for the construction steps?
Give one point for drawing AB at 7 centimeters and one for the 50-degree angle and the 5-centimeter mark. If the order is wrong but each step is correct, award one point.
Plan reteaching from the triangle scores
Look at whether most lost points came from the inequality, the angle sum, or the counting question. Then give the largest group a bag of straws to test for themselves. Finally, repeat the quiz to check progress.
Printable PDF · Test Answer Key
Grade 7 Drawing Geometric Figures and Constructing Triangles test answer key
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