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 UPQ581**

In the figure, ABCD is a square and EFD is an isosceles triangle. ∠AED = 72º and ∠ EFB = 51º. Find ∠ EDF.

*Solution:*

ABCD is a square,

∠ EBF = 90^{0} or right angle

Therefore, EBF is a right-angled triangle,

∠ BEF = 180^{0} – 90^{0} – 51^{0} = 39^{0}

AEB is a straight line,

∠ DEF = 180^{0} – 72^{0} – 39^{0} = 69^{0}

EDF is an isosceles triangle with DF = DE,

∠ DFE = ∠ DEF = 69^{0}

And,

∠ EDF = 180^{0} – 69^{0} – 69^{0} = __42 ^{0}__

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As of your question, is the answer 121? The number is multiple of 11 and dividing the number with 2,3,4,5,6 should give you remainder of 1. Cheer!

Yes! You got it right. Congo!