Answer:
He answered 20 questions correctly.
Step-by-step explanation:
25×.8(80%) = 20.
I believe A and B are the ones. As for explaining? hmm. I would honestly say that any number to the right of a number is a tenth of the place above it. But then again, it's optional to explain ;P
The constant should be added to form a perfect square trinomial will be 1/4. Then the correct option is D.
<h3>What is a quadratic equation?</h3>
It's a polynomial with a value of zero. There exist polynomials of variable power 2, 1, and 0 terms. A quadratic equation is an equation with one statement in which the degree of the parameter is a maximum of 2.
The expression is x² + x.
Then the constant should be added to form a perfect square trinomial.
Then the constant will be
The square of the half of the coefficient of the variable x is to be added to make a perfect square.
Then the constant will be 1/4.
Then the perfect square will be

More about the quadratic equation link is given below.
brainly.com/question/2263981
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(b)(b)=25 cm2
b2=25 cm2
√(b2)=√(25 cm2)
b= 5 cm
Please note the square root of 25 was taken, as well as the square root of cm2.
Perimeter=4b
Perimeter=4(5 cm)
Perimeter=20 cm
Step:
A circle of radius = 12.5 or diameter = 25 or circumference = 78.54 cm has an area of: 4.909 × 10-8 square kilometers (km²) 0.04909 square meters (m²)
Let’s says that x is the measure of the angle. X and it’s supplement are equal to 180. X and it’s complement are equal to 90. The supplement is s and the complement is c. S is times c which is the same as 3c.
3c + x = 180
C+x = 90
X = 90 - c
3c + 90 - c = 180
2c = 90
C = 45
The complement of. 45 degree angle is 45 degrees.
The angle is 45 degrees.