202k views
0 votes
Please help me, I need to know the measure of angle D

Please help me, I need to know the measure of angle D-example-1
User Hephaestus
by
5.3k points

1 Answer

6 votes

Answer: 135

==========================================

Step-by-step explanation:

If we started at point L, and moved to D, then moved to W, then we cover a quarter of the circle. We can see this through the inscribed angle theorem. Double the 45 degree angle at angle WIL to get 2*45 = 90, which is exactly 1/4 of a full 360 degree revolution.

So because arc LDW is 90 degrees, this means arc LIW is 360 - 90 = 270 degrees, which as expected is 270/360 = 3/4 of a full circle.

Use the inscribed angle theorem again to cut the arc measure in half to get the inscribed angle, so 270/2 = 135 is our answer.

note: the inscribed angle theorem is y = 2*x where x is the inscribed angle and y is the arc that the angle cuts off.

User Bitmusher
by
5.9k points
Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.