We are given:
- Parallelogram CDEF
- ∠C = 13x - 10
- ∠D = 5x + 10
To Find: ∠E
Concept Used:
- Adjacent angles of a Parallelogram are Supplementary
Finding the value of 'x':
Since adjacent angles of a parallelogram are Supplementary:
∠D + ∠C = 180
5x + 10 + 13x - 10 = 180 [replacing the values of angle C and D]
18x = 180
x = 10 [dividing both sides by 18]
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Finding Measure of Angle D:
We are given that:
∠D = 5x + 10
∠D = 5(10) + 10 [since x = 10]
∠D = 60°
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Finding the measure of ∠E:
∠D and ∠E are Adjacent angles
Since Adjacent angles are Supplementary:
∠D + ∠E = 180
60 + ∠E = 180
∠E = 120° [subtracting 60 from both sides]
Hence, the measure of ∠E = 120°