If two adjacent angles of a parallelogram are [tex](5x - 5)^{\circ}[/tex] and [tex](10x + 35)^{\circ}[/tex], then the ratio of these angles is

A. [tex]1: 3[/tex]
B. [tex]2: 3[/tex]
C. [tex]1: 4[/tex]
D. [tex]1: 2[/tex]



Answer :

To find the ratio of the adjacent angles of a parallelogram given by [tex]\((5x - 5)^\circ\)[/tex] and [tex]\((10x + 35)^\circ\)[/tex], we follow these steps:

1. Understand the properties of a parallelogram:
- The sum of the adjacent angles in a parallelogram is [tex]\(180^\circ\)[/tex].

2. Set up the equation based on the property:
[tex]\[ (5x - 5) + (10x + 35) = 180 \][/tex]

3. Simplify the equation:
[tex]\[ 5x - 5 + 10x + 35 = 180 \][/tex]
[tex]\[ 15x + 30 = 180 \][/tex]

4. Solve for [tex]\(x\)[/tex]:
- Subtract 30 from both sides:
[tex]\[ 15x = 150 \][/tex]
- Divide both sides by 15:
[tex]\[ x = 10 \][/tex]

5. Find the actual measures of the angles:
- Substitute [tex]\(x = 10\)[/tex] back into the expressions for the angles:
[tex]\[ A = 5x - 5 = 5(10) - 5 = 50 - 5 = 45^\circ \][/tex]
[tex]\[ B = 10x + 35 = 10(10) + 35 = 100 + 35 = 135^\circ \][/tex]

6. Calculate the ratio of the angles:
- The ratio of angle [tex]\(A\)[/tex] to angle [tex]\(B\)[/tex] is:
[tex]\[ \frac{A}{B} = \frac{45}{135} = \frac{1}{3} \][/tex]

7. Express the ratio in simplest form:
- Therefore, the ratio is:
[tex]\[ 1:3 \][/tex]

Thus, the ratio of the two given adjacent angles in the parallelogram is [tex]\(\boxed{1:3}\)[/tex].