Formula: SA = (2 × π(pie) × radius × height) + (2 × π(pie) × radius square.)
So the equation will be SA=( 2 × 3.14 × 2 × 4) + ( 2 × 3.14 × 2²)
Then, we will get ↓ ↓
SA= 50.24 + 25.12
<u>SA = 75.36 in</u><u>²</u>
set up a ratio to find the length:
15/12 = DE/16
cross multiply the 15 & 16:
15 * 16 = 240
divide that by 12 to get DE
240 / 12 = 20
DE = 20