# Trapezium internal angles

A trapezium where AB is parallel to CD, has angle A : angle D = 4 :5, angle B = 3x-15 and angle C = 4x+20. Find angle A, B, C and D.

**Result****Leave us a comment of example and its solution (i.e. if it is still somewhat unclear...):**

**Showing 1 comment:**

**Partho**

Let Angle A=4x, B= 3x-15, C=4x+20 and D=5x.

Using the property that sum of adjacent angles = 180 we get:

A + D = 180 or 4x+5x=180.

Solving we get x=20.

Substituting we get: A=80, B=100

Similarly, B+C=180 or

3x-15+4x+20=180

Solving we get x=25

Substituting we get: B=60, D=120.

Using the property that sum of adjacent angles = 180 we get:

A + D = 180 or 4x+5x=180.

Solving we get x=20.

Substituting we get: A=80, B=100

Similarly, B+C=180 or

3x-15+4x+20=180

Solving we get x=25

Substituting we get: B=60, D=120.

#### To solve this example are needed these knowledge from mathematics:

## Next similar examples:

- Internal angles IST

Determine internal angles of isosceles trapezium ABCD /a, c are the bases/ and if: alpha:gamma = 1:3 - Angle

Determine the size of the smallest internal angle of a right triangle which angles forming the successive members of the arithmetic sequence. - Triangle angles

In a triangle ABC the interior angle at the vertex C is twice as the internal angle at the point A. Outer angle at the point B measured 117 degrees. How big is the outer angle at the vertex A? - Alfa beta gama

The triangle's an interior angle beta is 10 degrees greater than the angle alpha and gamma angle is three times larger than the beta. Determine the size of the interior angles. - In a 2

In a thirteen sided polygon, the sum of five angles is 1274°, four of the eight angles remaining are equal and the other four are 18° less than each of the equal angles. Find the angles. . - Angles in ratio

The size of the angles of the triangle are in ratio x: y = 7: 5 and the angle z is 42° lower than the angle y. Find size of the angles x, y, z. - Angles of the triangle

ABC is a triangle. The size of the angles alpha, beta are in a ratio 4: 7. The angle gamma is greater than the angle alpha by a quarter of a straight angle. Determine angles of the triangle ABC. - Isosceles trapezoid

Perimeter of the isosceles trapezoid is 48 cm. One side is two times greater than the second side. Determine the dimensions of the trapezoid. - Largest angle of the triangle

What is the largest angle of the triangle if the second angle is 10° greater than twice the first and the third is 30° smaller than the second? - Linsys2

Solve two equations with two unknowns: 400x+120y=147.2 350x+200y=144 - Ball game

Richard, Denis and Denise together scored 932 goals. Denis scored 4 goals over Denise but Denis scored 24 goals less than Richard. Determine the number of goals for each player. - Men, women and children

On the trip went men, women and children in the ratio 2:3:5 by bus. Children pay 60 crowns and adults 150. How many women were on the bus when a bus was paid 4,200 crowns? - Geometric sequence 5

About members of geometric sequence we know: ? ? Calculate a_{1}(first member) and q (common ratio or q-coefficient) - Null points

Calculate the roots of the equation: ? - Warehouses

In the three warehouses, a total of 70 tons of grain was stored. In the second warehouse was stored 8.5t less and in the third 3.5t more than in the first. How many tons of grain was stored in each warehouse? - Three workshops

There are 2743 people working in three workshops. In the second workshop works 140 people more than in the first and in third works 4.2 times more than the second one. How many people work in each workshop? - Theorem prove

We want to prove the sentense: If the natural number n is divisible by six, then n is divisible by three. From what assumption we started?