Question

Keliling suatu belah ketupat 52 cm ,dan panjang salah satu diagonalnya 24 cm,luas belah ketupat adalah

Answer 1

Keliling belah ketupat = 4s

4s = 52
s = 52 / 4
s = 13

S² = 1/2d1² + 1/2d2²
1/2d2² = S² - 1/2d1²
1/2d2 = √S² - 1/2d1²
1/2d2 = √13² - 12²
= √169 - 144
= √25
= 5 cm

1/2d2 = 5 cm
d2 = 10 cm

Luas = 1/2 . d1 . d2
= 1/2 . 24 . 10
= 12 . 10
= 120 cm²

Answer 2

Sisi = K:4 = 52:4 = 13cm
diagonal lain = 2 x akar dr 13²-12²
= 2 x akar dr 169-144
= 2 x √25 = 2x5=10 cm
jadi,L = 1/2.d1.d2
= 1/2.24.10 = 120cm²