Page 244 - Start Up Mathematics_8 (Non CCE)

Construction of Quadrilateral Given Its Three Sides and Two Included Angles

Example 7: Construct a quadrilateral DEAR in which DE = 4 cm, EA = 5 cm, AR = 4.5 cm, –E = 60º
and –A = 90º. A (NCERT)

Solution: Construction: Draw a rough sketch of the 4.5 cm 90º
figure to be constructed. 5 cm
R
Steps of Construction
60º
1. Draw a line DE = 4 cm. E
D 4 cm
D 4 cm E
X

2. At point E on line DE, make –DEX = 60º using a
protractor.

X 60º
D 4 cm E
A

3. Taking E as centre and radius = 5 cm, draw 5 cm
an arc on EX intersecting it at point A.

60º
D 4 cm E

X
A

90º

Y 5 cm
4. At point A on line EA, make –EAY = 90º 60º
using a protractor. D 4 cm E

X
A
4.5 cm 90º

R 5 cm
5. Taking A as centre and radius = 4.5 cm, Y
draw an arc on AY intersecting it at point
R. Joint RD.
60º
Hence, DEAR is the required quadrilateral. D 4 cm E

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