3. Given right ADEF, DE = 2.1 and EF = 5.3. Use a calculator and inverse trigonometric ratios to find the unknown side lengths and angle measures. Round lengths to the nearest hundredth and angle measures to the nearest degree. 2.1 5.3

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**Problem 3: Solving for Unknown Side Lengths and Angles in Right ∆DEF**

**Given:** 
- Right triangle ∆DEF 
- \( DE = 2.1 \) 
- \( EF = 5.3 \) 

**Objective:** 
Use a calculator and inverse trigonometric ratios to find the unknown side lengths and angle measures. Round lengths to the nearest hundredth and angle measures to the nearest degree.

**Diagram Explanation:**
There is a right triangle labeled ∆DEF where:
- \( DE \) is one of the legs of the triangle with a length of 2.1 units.
- \( EF \) is the other leg of the triangle with a length of 5.3 units.
- \( DF \) is the hypotenuse, which we need to find.

### Steps:
1. **Find the Hypotenuse \( DF \):**

   Using the Pythagorean Theorem:
   \[
   DF = \sqrt{DE^2 + EF^2}
   \]
   \[
   DF = \sqrt{(2.1)^2 + (5.3)^2}
   \]
   \[
   DF = \sqrt{4.41 + 28.09}
   \]
   \[
   DF = \sqrt{32.50}
   \]
   \[
   DF \approx 5.70
   \]

2. **Find the Angle \( ∠DEF \):**

   Using the tangent function:
   \[
   \tan(∠DEF) = \frac{DE}{EF} = \frac{2.1}{5.3}
   \]

   Finding the angle using the arctangent function:
   \[
   ∠DEF = \tan^{-1}\left(\frac{2.1}{5.3}\right)
   \]
   \[
   ∠DEF \approx \tan^{-1}(0.3962) \approx 22^\circ
   \]

3. **Find the Angle \( ∠DFE \):**

   The sum of the angles in any triangle is 180 degrees. In a right triangle, we already have a 90-degree angle at \( ∠DEF \). Thus,
   \[
   ∠DFE = 90^\circ - ∠DEF
   \]
   \[
   ∠DFE = 90^\
Transcribed Image Text:**Problem 3: Solving for Unknown Side Lengths and Angles in Right ∆DEF** **Given:** - Right triangle ∆DEF - \( DE = 2.1 \) - \( EF = 5.3 \) **Objective:** Use a calculator and inverse trigonometric ratios to find the unknown side lengths and angle measures. Round lengths to the nearest hundredth and angle measures to the nearest degree. **Diagram Explanation:** There is a right triangle labeled ∆DEF where: - \( DE \) is one of the legs of the triangle with a length of 2.1 units. - \( EF \) is the other leg of the triangle with a length of 5.3 units. - \( DF \) is the hypotenuse, which we need to find. ### Steps: 1. **Find the Hypotenuse \( DF \):** Using the Pythagorean Theorem: \[ DF = \sqrt{DE^2 + EF^2} \] \[ DF = \sqrt{(2.1)^2 + (5.3)^2} \] \[ DF = \sqrt{4.41 + 28.09} \] \[ DF = \sqrt{32.50} \] \[ DF \approx 5.70 \] 2. **Find the Angle \( ∠DEF \):** Using the tangent function: \[ \tan(∠DEF) = \frac{DE}{EF} = \frac{2.1}{5.3} \] Finding the angle using the arctangent function: \[ ∠DEF = \tan^{-1}\left(\frac{2.1}{5.3}\right) \] \[ ∠DEF \approx \tan^{-1}(0.3962) \approx 22^\circ \] 3. **Find the Angle \( ∠DFE \):** The sum of the angles in any triangle is 180 degrees. In a right triangle, we already have a 90-degree angle at \( ∠DEF \). Thus, \[ ∠DFE = 90^\circ - ∠DEF \] \[ ∠DFE = 90^\
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