Look at the picture.
To find the area of triangle DBC we need to find its base, x, and its height, h.
Triangle ABC is a right triangle, so using the Pythagorean theorem we can find x.

Now look at triangles ABC and DBH. They both are right triangles and have the same angle α. That means they're similar and their corresponding sides are proportional. The ratio of the side opposite to angle α to the hypotenuse is the same in both triangles - so the ratio of h to 1 is the same as the ratio of 3 to 5.

The base x is 4, the height h is 3/5. Calculate the area:

The area of triangle DBC is 6/5.
20,194+9,283 - 372 = 29,105
Answer:
-4/9
Step-by-step explanation:
flip -3/5
4×5 / 15×-3
20/-45
÷5 ÷5
-4/9
Time is the independent variable
Answer:
x = 55
Step-by-step explanation:
A triangle equals 180 degrees, b will be used to find the missing angle.
21 + 34 + b = 180
55 + b = 180
subtract 55 from both sides
b = 125
A straight line is 180 degrees and the b, the missing angle, and x are supplementary angles so
125 + x = 180
x = 55