Question

Please help I don't understand!

Answer 1

3.8

Explanation:

1. Use sine rule

d/sin(D) = f/sin(F) (d=EF, f=DE=3)

2. cross multiply

d=f(sin(D)/sin(F)) = 3(sin(75)/sin(50))=3.783

Answer 2

(b) 3.8

Explanation:

Often, simple relations will help you solve geometry problems. Here, you only need to know that larger angles are opposite longer sides.

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The angle opposite side EF is angle D, which is 75°. That angle is larger than angle F, which is opposite the side marked as having length 3.

This means EF > 3.

There is only one answer choice greater than 3. Choice B is 3.8.

EF ≈ 3.8

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The only "work" is remembering that larger angles are opposite longer sides.