PDF chapter test TRY NOW

  • Depending upon the lengths of the sides and diagonal, create a triangle of PQR based on SSS construction.
YCIND13052022_3741_TN_Class8_Geometry.svg
  • Make an arc (point S) at a certain distance from P.
YCIND13052022_3741_TN_Class8_Geometry_1.svg
  • Make an arc at a certain distance from point R on the earlier arc on S. Name the two points intersection as S.
 YCIND13052022_3741_TN_Class8_Geometry_1.svg
  • P and R join S. The quadrilateral PQRS will be achieved.
YCIND13052022_3741_TN_Class8_Geometry_2.svg
Example:
Construct a quadrilateral ABCD with the following measurements.
 
AB = 4.5 cm, BC = 5.5 cm, CD = 4cm, AD = 6cm, AC = 7cm.
 
Step 1:Draw side BC = 5.5 cm and cut arcs above it from B (4.5 cm) and C (7 cm). Mark the intersection as A. Join AB and AC.
 
YCIND13052022_3741_TN_Class8_Geometry_3.svg
 
Step 2: Draw and arc from A equal to 6 cm which is the length of AD.
 
YCIND13052022_3741_TN_Class8_Geometry_4.svg
 
Step 3: Draw and arc from C equal to 4 cm which is the length of CD. Mark the intersection as D and join AD and CD.
 
YCIND13052022_3741_TN_Class8_Geometry_5.svg
 
Thus, the ABCD is a required quadrilateral.
 
Calculate Area of quadrilateral:

Area of the quadrilateral ABCD = \frac {1}{2} \times d \times h_1 + h_2 sq. units
 
= \frac{1}{2} × 10 (1.9 +2.3)
 
= 5\times 4.2
 
= 21 cm².