Complementary angles ⇒ the angles add up to 90°
∠A and ∠B are complementary ⇒ ∠A + ∠B = 90°
∠A + ∠B = 90°
Plug in the values for ∠A and ∠B:
(3x - 8) + (5x + 10) = 90
Open the brackets:
3x - 8 + 5x + 10 = 90
Combine like terms:
8x + 2 = 90
Subtract 2 from both sides:
8x = 88
Divide both sides by 8:
x = 11
Answer: x = 11
Answer:
Breadth = 15 cm
Step-by-step explanation:
Area = length x breadth
315 = 21 x breadth
[ dividing both sides by 21 ]

Answer:
Step-by-step explanation:
a) A square is a rectangle. True
Reason: Property of Rectangle: (i) Opposite sides are equal and parallel. (ii) Each angle is 90 (iii) Diagonals are equal and bisect each other.
A square hold all these properties. A square is a rectangle.
b) A polygon with 21 sides has 432 possible diagonals. False
Reason: Number of diagonals of a polygon = 
n --> number of sides of a polygon.
=
= 189 diagonals
c) All three angles in an Isosceles triangle are equal. False
Reason: In an isosceles triangle, two angles are equal.
If three angles are equal, then that is an equilateral triangle.
d) The measures of the exterior angles of a nonagon, a nine-sided figure, have a sum of 360°. True.
Reason: The sum of measures of the exterior angles of any polygon is 360
The numbers are 15, 17 and 19
Answer:
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Step-by-step explanation: