Read posting **Sarin learns Lines and Angles (Math concept)** to understand the concept of lines and angles. Read also posting **Sarin learns Shapes and Solids in school (Math Concept)** to know about shapes.

Upper primary school mathematics question UPQ74

Find the sum of angles a, b , c and d of the figure below.

*Solution:*

∠ a + ∠ b + ∠ e + ∠ f = 360^{0} (4-sided object)

∠ e = ∠ d + 40^{0} (Triangle)

∠ f = ∠ c + 40^{0} (Triangle)

∠ e + ∠ f = ∠ d + ∠ c + 40^{0 }+ 40^{0} = ∠ d + ∠ c + 80^{0}

∠ a + ∠ b + ∠ e + ∠ f = ∠ a + ∠ b + ∠ d + ∠ c + 80^{0} = 360^{0}

∠ a + ∠ b + ∠ c + ∠ d = 360^{0} – 80^{0 }= 280^{0}

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