Answer:
9.3
Step-by-step explanation:
Step 1: Calculate. We calculate the square root of 87 to be: √87 = 9.32737905308882.
Step 2: Reduce. 9.32.
Step 3: Round. Round 9.32 so you only have one digit after the decimal point to get the answer: 9.3.
An = a1+d*(n-1)
a11 = 75-8*(11-1) = -5
The answer is 90 because 360/4 (since it is a quadrilateral) is 90 degrees
