apa jawaban soal yg ada di atas

8. L = (a+b) × t ÷ 2

3.060 = (100+70) × t ÷ 2

3.060 = 170 × t ÷ 2

3.060 = 85 × t

t = 3.060 ÷ 85

t = 36 cm



9. L = phi × r^2

= 22/7 × 21^2

= 22/7 × 441

= 22 × 63

= 1.386