Page 249 - Start Up Mathematics_8 (Non CCE)

X Y
O

3. Taking D as centre and radius = 7.4 cm, draw 7.4 cm
an arc on line RY intersecting it at point O.
Join OD.

90º
D 6 cm R

X Y
P O

7.4 cm
4. Taking O as centre and radius = 6 cm, draw an
arc on DX intersecting it at P. Join OP.
Hence, DROP is the required rectangle.

90º

D 6 cm R

EXERCISE 15.6

1. Construct a square DEBT in which DE = 3.5 cm.
2. Construct a square LAST in which diagonal AT = 5.8 cm.
3. Construct a rectangle DICE in which DI = 5.5 cm and IC = 4.5 cm.
4. Construct a rectangle CORD in which CO = 4.5 cm and diagonal CR = 6 cm.

AT a Glance

1. To construct a quadrilateral uniquely, it is necessary to know at least five of its building blocks.
2. To construct a quadrilateral, measurements of the following are sufficient:
(a) Four sides and one diagonal
(b) Three sides and two diagonals
(c) Two adjacent sides and three angles
(d) Three sides and two included angles
(e) Four sides and one angle
3. The five building blocks, in order to be sufficient for construction of quadrilateral, must also satisfy
(wherever relevant):
(a) The triangle inequality property
(b) Angle-sum property of a quadrilateral

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