Question

Suatu segitiga jika alasnya dikurangi 10% dan tingginya ditambah 10%, maka luasnya akan....
A. Tetap
B. Berkurang 0,5%
C. Bertambah 0,5%
D. Berkurang 1%
E. Berkurang 1%

Answer 1

Verified answer

A2 = a1 - 10% a1
a2 = 90% a1

t2 = t1 + 10% t1
t2 = 110% t1

L1 : L2 = (1/2 . a1 . t1) : (1/2 . a2 . t2)
L1 : L2 = (a1 . t1) : (90% a1 . 110% t1)
L1 : L2 = 1 : (9900/10000)
L1 : L2 = 100 : 99
L2 = 99% L1

kesimpulan : luas 'berkurang 1%'
pilihan : D & E

mohon koreksi...
senang bisa membantu :)

Answer 2

Verified answer

Luas = 1/2 a . t
Alas berkurang 10% => (100 - 10)%a = 90% a
Tinggi bertambah 10% => (100 + 10)%t = 110%t

Luas = 1/2 . 90%a . 110%t
= 90/100 . 110/100 . 1/2 a . t
= 99/100 . 1/2 a . t
= 99% . 1/2 a . t
Artinya luas berkurang (100 - 99)% = 1% =