# Sarin learns Shapes and Solids in school part 30 (Math Question)

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The blog postings are about the Singapore Math. The readers can learn from the postings on Solving Singapore Primary School Mathematics. The blog presenting the Math Concept, Math Questions with solutions that teaches in Singapore Primary Schools. You or the kids can learn the skills to deal with Math Modeling, 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 Angle and Shape.

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

Upper primary school mathematics question UPQ270

In the figure below, BCDE is a rhombus and DEA is a straight line. Find the value of ∠ b.

Solution:

BCDE is a rhombus, line DB is a bi-sector of ∠ EDC

∠ BDE = ∠ BDC = 250

∠ EDC = 250 + 250 = 500

AD is a straight line, EB//DC as BCDE is a rhombus

∠ AEB = ∠ EDC = 500

AEB is a triangle

∠ b = 1800 – 780 – 500 = 520