MathBrush

Practice

Same pattern as Parallelogram BCDE — find ∠EAB. New numbers, new story. Try each one on paper, then check the working below — or watch it drawn out, the same way the problem above is.

Question 1

A framer is building a triangular display easel EAD, braced by a parallelogram strut BCDE, where B lies on strut AD. The two strut pieces AB and BE are cut to equal length. Given angle DBC = 42° and angle BCD = 66°, find angle EAB.

Triangular easel frame EAD with parallelogram brace BCDE fixed across it, B lying on AD, and AB equal to BE.42°66°?ABCDE

Work it out on paper, then check below. ▶ See the working

Question 2

A kite maker cuts a triangular kite skeleton EAD from bamboo, with a parallelogram sail panel BCDE stitched across it; B lies on the spine AD. The struts AB and BE are equal in length. Given angle DBC = 51° and angle BCD = 59°, find angle EAB.

Triangular kite skeleton EAD with parallelogram sail BCDE stitched across it, B lying on spine AD.51°59°?ABCDE

Work it out on paper, then check below. ▶ See the working

Question 3

A landscaper installs a triangular trellis EAD in a garden bed, with a parallelogram lattice panel BCDE fitted inside it; B lies on the trellis edge AD. The posts AB and BE are equal in length. Given angle DBC = 46° and angle BCD = 70°, find angle EAB.

A triangular garden trellis EAD with a parallelogram lattice panel BCDE fitted inside it, B lying on edge AD.46°70°?ABCDE

Work it out on paper, then check below. ▶ See the working

The working