find the area of a rectangular octagon of side 7 cm Question find the area of a rectangular octagon of side 7 cm in progress 0 Math Rose 10 months 2021-08-20T17:01:09+00:00 2021-08-20T17:01:09+00:00 1 Answer 0 views 0
Answers ( )
Answer:
AL=5cm
We know that all sides of regular octagon are equal.
∴ AB=BC=CD=DE=EF=FG=GH=HA=7cm
⇒ HC=GD=15cm
⇒ Area of trapezium ABCH=21(AH+HC)×AL
=21(7+15)×5
=21×22×5
=55cm2
Area of trapezium ABCH= Area of trapezium GDEF
∴ Area of trapezium GDEF=55cm2
⇒ Now, are of rectangle HCDG=l×b
=15×7
=105cm2
⇒ Area of octagon ABCDEFGH= Area of trapezium ABCH+Area of trapezium GDEF+Area of rectangle HCDG
=(55+55+105)cm2
=215cm2
Step-by-step explanation:
Hope it helps you