Without a calculator, calculate the value of (a) and simplify (b):

👉🏼 (a)

👈🏼 (b)

👆🏼 Write 5.3867 to 2 decimal places

👇🏼 What is the sum of the interior angles in a decagon?

🖐🏼 What is the size of each interior angle in a regular decagon?