(18/50)

L = √(s × (s – a)(s – b)(s – c)

L = √(18 × (18 – 10)(18 – 14)(18 – 12)

L = √(18 × 8 × 4 × 6)

L = √(144 × 4 × 6)

L = √(576 × 6)

L = √3.456

L = 12√24 cm²

K = s1 + s2 + s3

K = 10 + 14 + 12

K = 24 + 12

K = 36 cm

» Penyelesaian Soal «

[ Soal ]

Diketahui sebuah segitiga sembarang abc memiliki sisi a sebesar 10 cm, sisi b sebesar 14 cm dan sisi c sebesar 12 cm. Berapakah luas dan kelilingnya?

_______________

Sisi a = 10 cm

Sisi b = 14 cm

Sisi c = 12 cm

[ Luas ]

•Mencari sisi

• s = ( a + b + c ) ÷ 2
• s = ( 10 cm + 14 cm + 12 cm )÷ 2
• s = ( 10 + 26 cm ) ÷ 2
• s = ( 36 cm ÷ 2 )
• s = 18 cm

Luas = s × ( s – a ) × ( s – b ) × ( s – c )

• L = s × ( s – a ) × ( s – b ) × ( s – c )

L = 18 cm × ( 18 cm – 10 cm ) × ( 18 cm – 14 cm ) × ( 18 cm – 12 cm )

• L = 18 × ( 8 cm × 4 cm × 6 cm )
• L = 18 × ( 32 cm × 6 cm )
• L = ( 18 × 192 cm )
• L = 1.536 cm
• L = √ 1.536 cm
• L = 12√24 cm²

[ Keliling ]

Keliling segitiga = a + b + c

K = a + b + c

K = 10 cm + 14 cm + 12 cm

K = 10 cm + 26 cm

K = 36 cm

Kesimpulan

• Luas = 12√24 cm²
• Luas = 12√24 cm²Keliling = 36 cm

Semoga Bisa Bermanfaat-!