Inscribed Triangle on Diameter - Missing Angle (Level 1)

This math topic focuses on the geometry of circles, specifically working with inscribed triangles where one side is the diameter. The main skill practiced is solving for missing angles within these triangles. Each problem presents a different triangle inscribed in a circle, with one angle given and the student required to find another. The problems invite the student to apply the theorem that a triangle inscribed in a circle and subtended by the diameter is a right triangle. Various angle values are presented in a multiple-choice format for students to select the correct answer.

Work on practice problems directly here, or download the printable pdf worksheet to practice offline.

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Geometry of Circles - Inscribed Triangle on Diameter - Missing Angle Worksheet

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Math worksheet on 'Geometry of Circles - Inscribed Triangle on Diameter - Missing Angle (Level 1)'. Part of a broader unit on 'Geometry - Intermediate - Intro' Learn online: app.mobius.academy/math/units/geometry_intermediate_intro/
1
An svg image showing a math problem
Find angle BPY in degrees given that BYP is 30º and PY forms a diameter
a
60º
b
150º
c
90º
d
120º
e
105º
f
15º
2
An svg image showing a math problem
Find angle RZY in degrees given that RYZ is 40º and ZY forms a diameter
a
50º
b
80º
c
95º
d
125º
e
25º
f
35º
3
An svg image showing a math problem
Find angle NRD in degrees given that NDR is 30º and RD forms a diameter
a
75º
b
30º
c
105º
d
60º
e
90º
f
4
An svg image showing a math problem
Find angle BCD in degrees given that BDC is 20º and CD forms a diameter
a
70º
b
25º
c
55º
d
40º
e
100º
f
115º
5
An svg image showing a math problem
Find angle ZBN in degrees given that ZNB is 60º and BN forms a diameter
a
b
90º
c
105º
d
60º
e
30º
f
15º
6
An svg image showing a math problem
Find angle BMY in degrees given that BYM is 40º and MY forms a diameter
a
65º
b
50º
c
110º
d
95º
e
80º
f
35º
7
An svg image showing a math problem
Find angle MXN in degrees given that MNX is 20º and XN forms a diameter
a
70º
b
145º
c
55º
d
85º
e
10º
f
100º
Geometry of Circles - Inscribed Triangle on Diameter - Missing Angle (Level 1) - Mobius Math