tentukan keliling irisan lingkaran x^2+y^2=20 dan (x-4) ^2+(y-4) ^2=68!

x²+y²=20
pusat= (0,0) jari=√20

(x-4)² +( y-4)² = 68!
pusat =(4,4) jari=√68
↓
x²-8x+16 +y²-8y+16=68
x²+y²-8x-8y-36=0

eliminasi=
x²+y²=20
x²+y²-8x-8y=36
hasilnya 8x+8y=-16 →x+y=-2 →x=-y-2

subtitusikan ke x²+y²=20
→ (-y-2)²+y²=20
→ y²+4y+4+y²=20
→2y²+4y-16=0
→y²+2y-8=0
(y+4)(y-2)
y= -4 dan y= 2
x= 2 dan x=-4
titik = (2,-4) dan (-4,2)

cari jarak= √(x2-x1)²+(y2-y1)²
= √(-4-2)²+(2-(-4))²
= √(-6)² + 6²
= √36+36
= √72
= 6√2

cari cos pers. 1
cos = (√20)²+(√20)²-(6√2)²/2.√20.√20
cos =20+20-72 / 40
cos = -32/40
cos = -4/5
arc cos = 143,1°

cari cos pers. 2
cos = (√68)²+(√68)²-(6√2)²/2.√68.√68
cos = 68+68-72 / 136
cos = 64 / 136
cos = 8 / 17
arc cos = 61,9°


cari irisan
= L tembereng pers.1 + L tembereng pers.2

*L tembereng pers.1
= luas juring - luas segitiga
= 143,1/360. 3,14.√20.√20-½.√20.√20.sin143,1
= 24,963 - 6,004
= 18,959

*L tembereng pers.2
= luas juring - luas segitiga
= 61,9/360. 3,14.√68.√68-½.√68.√68.sin61,9
= 36,713 - 29,988
= 6,725


cari irisan
= L tembereng pers.1 + L tembereng pers.2
= 18,959 + 6,725
= 25,684


maaf kalau salah ,,hehe