Finding Missing Angles in Triangles

The video tutorial covers finding missing angles in triangles, starting with a warm-up exercise on solving equations. It explains the triangle angle sum theorem, which states that the sum of the interior angles of a triangle is 180 degrees. The tutorial includes several examples of finding missing angles, both simple and complex, involving expressions. It concludes with a final example and outlines expectations for upcoming assignments and live class sessions.

What is the first step in solving the equation X + 65 + 32 = 180?

• Subtract 65 from both sides

• Add 32 to both sides

• Combine like terms

• Divide by 2

Tags

CCSS.6.EE.B.7

How many degrees are in a triangle?

• 90 degrees

• 360 degrees

• 180 degrees

• 270 degrees

Tags

CCSS.8.G.A.5

What is the triangle angle sum theorem?

• The sum of the measures of the interior angles of a triangle is 180 degrees

• The sum of the measures of the interior angles of a triangle is 360 degrees

• The sum of the measures of the exterior angles of a triangle is 360 degrees

• The sum of the measures of the exterior angles of a triangle is 180 degrees

Tags

CCSS.8.G.A.5

If Joan knows two angles in a triangle are 65 and 57 degrees, what is the measure of the third angle?

• 40 degrees

• 50 degrees

• 60 degrees

• 58 degrees

Tags

CCSS.8.G.A.5

What is the measure of the missing angle if the known angles are 40 and 90 degrees?

• 50 degrees

• 30 degrees

• 60 degrees

• 70 degrees

Tags

CCSS.7.G.B.5

In a triangle with angles 20 degrees and 130 degrees, what is the measure of the third angle?

• 20 degrees

• 50 degrees

• 30 degrees

• 40 degrees

Tags

CCSS.8.G.A.5

What is the value of X if the angles in a triangle are given as 8x - 11, 15x, and 3x + 9?

• 7

• 5

• 6

• 8

Tags

CCSS.8.G.A.5

Why was Timothy's answer of 7 degrees incorrect for the measure of angle K?

• He did not solve for X

• He stopped too soon and did not calculate the actual angle

• He added the angles incorrectly

• He used the wrong theorem

Tags

CCSS.8.G.A.5

What is the measure of angle K if X is found to be 7?

• 75 degrees

• 105 degrees

• 90 degrees

• 60 degrees

Tags

CCSS.7.G.B.5

If Steven's triangular garden has angles of 50 degrees and 90 degrees, what is the measure of the third angle?

• 60 degrees

• 50 degrees

• 40 degrees

• 30 degrees

Tags

CCSS.8.G.A.5