Examples with solutions for Sum and Difference of Angles: Calculate Angles in Quadrilaterals

Exercise #1

It is known that angles A and D are equal to 90 degrees

Angle DEB is equal to 95 degrees

Angle BCE is equal to 55 degrees

Complete the value of angle BAG based on the data from the figure.

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Video Solution

Step-by-Step Solution

Note that angle BAG is part of angle BAD.

Therefore, we can write the following equation:

BAG+GAD=BAD BAG+GAD=BAD

From the data given in the question, we know that angle A is equal to 90 degrees, and angle GAD is equal to 50.

Let's substitute the known values into the formula:

BAG+50=90 BAG+50=90

We'll move terms to one side and maintain the appropriate sign:

BAG=9050 BAG=90-50

BAG=40 BAG=40

Answer

40

Exercise #2

It is known that angles A and D are equal to 90 degrees

Angle DEB is equal to 95 degrees

Complete the value of angle GDC based on the data from the figure.

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Video Solution

Step-by-Step Solution

Note that the GDC angle is part of the EDC angle.

Therefore, we can write the following expression:

GDC+EDG=EDC GDC+EDG=EDC

Since we know that angle D equals 90 degrees, we will substitute the values in the formula:

GDC+40=90 GDC+40=90

We will simplify the expression and keep the appropriate sign:

GDC=9040 GDC=90-40

GDC=50 GDC=50

Answer

50

Exercise #3

It is known that angles A and D are equal to 90 degrees

Angle BCE is equal to 55 degrees

Angle DEB is equal to 95 degrees

Angle FCD is equal to 50 degrees

Complete the value of angle CEB based on the data from the figure.

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Video Solution

Step-by-Step Solution

Let's pay attention to the data in the question.

We know that angle DEB is equal to 95 degrees.

Let's break it down into an addition exercise:

CEB+CED=DEB CEB+CED=DEB

Now let's substitute the known data into the formula:

CEB+70=95 CEB+70=95

We'll move a term and keep the appropriate sign:

CEB=9570 CEB=95-70

CEB=25 CEB=25

Answer

25

Exercise #4

It is known that angles A and D are equal to 90 degrees

Angle BCE is equal to 55 degrees

Angle DEB is equal to 95 degrees

Angle FCD is equal to 50 degrees

Complete the value of angle BCD based on the data from the figure.

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Video Solution

Step-by-Step Solution

Let's look at angle BCD and break it down into the angles that compose it:

BCD=BCF+FCE+ECD BCD=BCF+FCE+ECD

Note that the angle values we wrote in the formula are given to us in the diagram, and now we'll substitute them:

BCD=25+30+20 BCD=25+30+20

BCD=75 BCD=75

Answer

75

Exercise #5

Angles A and D are both equal to 90 degrees.

Angle DEB is equal to 95 degrees.

Calculate the value of angle BCE based on the data in the figure.

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Video Solution

Step-by-Step Solution

Let's break down angle BCE into an angle addition exercise:

BCE=BCF+FCE BCE=BCF+FCE

Now let's input the known data from the diagram:

BCE=25+30 BCE=25+30

BCE=55 BCE=55

Answer

55

Exercise #6

The rectangle ABCD is shown below.

Angle CAD is equal to 45 degrees.

Calculate the remaining angles in the rectangle.

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Video Solution

Answer

CAD = BCA = 30
ACD = CAB = 60

Exercise #7

It is known that angles A and D are equal to 90 degrees

Angle BCE is equal to 55 degrees

Angle DEB is equal to 95 degrees

Complete the value of angle FCD based on the data from the figure.

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Video Solution

Answer

50