The blog postings are about the Singapore Math. The readers can learn from the postings on Solving Singapore Primary School Mathematics. The blog presents the Math Concept, the Math Questions with solutions that teaches in Singapore Primary Schools. You or the kids can learn the skills to deal with the Math Modeling, the Math Problem Solving and the Problem Sum from Lower Primary School to Upper Primary School level after reading the blog postings. This posting is an upper primary school math question on Angles and Shapes.

Read the posting on **Sarin learns Shapes and Solids in school (Math Concept)** to know about shapes.

Read the posting on ** Sarin learns Lines and Angles (Math concept)** to understand the concept of lines and angles.

*Challenge yourself with the question before look for the given solution‼!*

**Upper primary school mathematics question UPQ574**

In the figure, ABDE is a trapezium and ABC is an isosceles triangle. ∠BAE = 40^{0}, ∠CBD = 20^{0} and ∠CDE = 89^{0}.

a. Find ∠BCA.

b. Find ∠ AED.

*Solution:*

a. ABDE is a trapezium,

∠ABD = 180^{0} – 40^{0} = 140^{0}

∠ABC = 140^{0} + 10^{0} = 150^{0}

ABC is an isosceles triangle with AB = BC,

∠ BCA = ∠ BAC = (180^{0} – 150^{0}) ÷ 2 = __15 ^{0}__

b. ADC is a straight line,

∠EDC is the exterior angle of triangle AED

∠EAD = 40^{0} – 15^{0} = 25^{0}

∠AED = 89^{0} – 25^{0} = __54 ^{0}__