Find the area of a regular octagon with a side length of 10 cm. Round to the nearest tenth.

The question keeps telling me to STOP!  Never mind.

The octagon is 8 isosceles triangles.  Each has common side r and base 10.  The central angle is 360/8 = 45°.  By the Law of cosines,

10² = r² + r² - 2 r² cos 45° = 2r²(1 - √2/2) = r²(2-√2)

r² = 100/(2-√2)

The area of a triangle with sides a,b and included angle C is (1/2)ab sin C. Our 8 octagon isosceles triangles each have sides r and r and included angle 45° so our total area, 8 triangles, is

A = 8(1/2) r² sin 45° = (400/(2-√2)) (√2/2) × (2+√2)/(2+√2) = 200(1+√2)

A ≈482.84271

482.8 sq cm

the answer is c. hope this !

step-by-step explanation:

the camry sales+accord sale=828,000. to make it so the two numbers are 18 thousand apart and still equal 828,000, you first need to find out what half of 828,000 is. 828,000/2=414,000. for the two numbers to equal 828,000, you have to add the same amount as you subtract from the middle. in this case, the number is 9,000 because it's half of 18,000. to equal 828,000, you have to add 9,000 to 414,000 for the camry and subtract 9,000 from 414,000 for the accord. 414,000+9,000=423,000.

414,000-9,000=405,000.

423,000+405,000=828,000.

423,000-405,000=18,

hope it