BC=48cm,CD=17cm,AD=40cm ∠A=∠B=90∘ Formula used: Area of rectangle = Length × Breadth Area of right-angled triangle =1∕2× Base × Perpendicular Hypotanesous 2= Base 2+ Perpendicular 2 Calculation:
In △DEC, Perpendicular (DE)=√(DC2−EC2) ⇒DE=√(172−82) ⇒DE=√(289−64) ⇒DE=√225=15cm Now, Area of △DEC ⇒1∕2×EC×DE ⇒1∕2×8×15 ⇒1∕2×120=60cm2 Now, AB=DE=15cm Area of rectangle ABED ⇒AB×AD ⇒15×40=600cm2 Thus, Area of quadrilateral ABCD ⇒ Area of △DEC+ Area of rectangle ABED ⇒60+600 ⇒660cm2