My Learning Cart
?
Categories
Account

In triangle DEF, if DE = 10 cm, DF = 15 cm, and angle E = 45 degrees, what is th

₹0.0
Login to Download
  • 📥 Instant PDF Download
  • ♾ Lifetime Access
  • 🛡 Secure & Original Content

What’s inside this PDF?

Question: In triangle DEF, if DE = 10 cm, DF = 15 cm, and angle E = 45 degrees, what is the length of EF using the Law of Cosines?

Options:

  1. 5√2 cm
  2. 10√2 cm
  3. 15√2 cm
  4. 20 cm

Correct Answer: 5√2 cm

Solution: 

Using the Law of Cosines: EF² = DE² + DF² - 2 * DE * DF * cos(E). EF² = 10² + 15² - 2 * 10 * 15 * cos(45°) = 100 + 225 - 150√2. Thus, EF = 5√2 cm.

In triangle DEF, if DE = 10 cm, DF = 15 cm, and angle E = 45 degrees, what is th

Practice Questions

Q1
In triangle DEF, if DE = 10 cm, DF = 15 cm, and angle E = 45 degrees, what is the length of EF using the Law of Cosines?
  1. 5√2 cm
  2. 10√2 cm
  3. 15√2 cm
  4. 20 cm

Questions & Step-by-Step Solutions

In triangle DEF, if DE = 10 cm, DF = 15 cm, and angle E = 45 degrees, what is the length of EF using the Law of Cosines?
  • Law of Cosines – A formula used to find a side of a triangle when two sides and the included angle are known.
  • Trigonometric Functions – Understanding how to calculate cosine values, especially for common angles like 45 degrees.
  • Triangle Properties – Knowledge of triangle side lengths and angles, and how they relate to each other.
Soulshift Feedback ×

On a scale of 0–10, how likely are you to recommend The Soulshift Academy?

Not likely Very likely
Home Practice Performance eBooks