# help please!?

given angle DBC = 20 degrees, AB=25 and DC=7, calculate the following measurements.

angle A=

length of AD=

area of triangle ABC=

### 5 Answers

- AshLv 71 month agoFavourite answer
tan ∠DBC = DC/BD

tan 20° = 7/BD

BD = 7/tan 20°

BD ≈ 19

sin ∠A = BD / AB

∠A = arcsin (19/25)

∠A = 49.5°

AD = √(AB² - BD²) = √(25² - 19²) ≈ 16

Area ΔABC = ½(AC * BD) = ½((AD + DC) * BD) = ½((16 + 7) * 19) = 218.5

- Log in to reply to the answers

- KrishnamurthyLv 71 month ago
given angle DBC = 20 degrees, AB = 25, and DC = 7, calculate the following measurements.

angle A = 53.13 degrees

length of AD = 15

area of triangle ABC = 220 units^2

- Log in to reply to the answers

- sepiaLv 71 month ago
Given angle DBC = 20°, AB = 25, and DC = 7,

calculate the following measurements:

Since ABD is a right triangle in which the hypotenuse measures 25

the other sides of the triangle are 15 and 20

Because it is a right triangle one angle is obviously 90°.

The other two are approximately 36.87° and 53.13°.

Angle A = 53.13°

Length of AD = 15

Length of AC = 22

Area of triangle ABC = 220 units^2

Angle C = 70°

- Log in to reply to the answers

- What do you think of the answers? You can sign in to give your opinion on the answer.
- JimLv 71 month ago
Since angles inside of a triangle add to 180, and a right angle is 90

1) 180 -90 -20 = 70° for angle A

2) Use SOHCAHTOA

3) ½bh, but you must calc BD

- julianna1 month agoReport
You didn’t calculate angle A, you calculated angle C

- Log in to reply to the answers