`Delta ABC ` में,
` " "AC^(2) =5^(2) =25`
` AB^(2) +BC^(2) =3^(2) +4^(2) =25`
` therefore " " AC^(2) =AB^(2) +BC^(2) `
`
`rArr " "Delta ABC ` समकोणीय है|
तथा ` angle ABC =90^(@)`
` Delta ABC` का क्षेत्रफल
` " "= (1)/(2) xxBC xxAB =(1)/(2)xx4 xx3 =6 ` सेमि `""^(2 ) `
` Delta ACD` में
माना `a= AC=5` सेमि `b, =AD=5` सेमि,तथा `c=DC=4` सेमि|
` therefore " "s = (a++b+c) /( 2)=( 5+5+4)/(2) ` सेमि =7 सेमि
अब `Delta ACD ` का क्षेत्रफल `=sqrt (s(s-a)(s-b)(s-c))`
` " " sqrt (7(7-5)(7-5)(7-4)) `
` therefore square ABCD` का क्षेत्रफल
` " " = Delta ABC ` का क्षेत्रफल +`Delta ACD`का क्षेत्रफल
` " " = 6` सेमि `""^(2)` +9 .2 सेमि `""^(2 ) `
` " " = 15.2` सेमि ` ""^(2 ) `
