Is there any numbers to answer the question?
Answer:
Ancient Greeks
Beginning in the 6th century BC with the Pythagoreans, with Greek mathematics the Ancient Greeks began a systematic study of mathematics as a subject in its own right. Around 300 BC, Euclid introduced the axiomatic method still used in mathematics today, consisting of definition, axiom, theorem, and proof.
Step-by-step explanation:
Answer:
Step-by-step explanation:
To properly apply the substitution method, it will be better for us to rearrange the system of equations to have similar variables on the same side


We can simply evaluate equation 1 to have

y = -20
From the first equation alone, we can evaluate the value of y as -20. This is because only one unknown is present in equation one, hence a single equation is sufficient enough to evaluate it. If to unknowns were present, the two equations would have been utilized to evaluate the solution.
Answer:
Perimeter of the quadrilateral PQRS is 25 units
Step-by-step explanation:
From the figure attached,
PQ is a tangent to the given circle so m∠PQR = 90°
Now we apply Pythagoras theorem in the ΔPQR,
PR² = PQ² + QR²
(PT + TR)²= PQ² + 5²
(4 + 5)² = PQ² + 25
81 = PQ² + 25
PQ = √(81 - 25)
= √56
≈ 7.5 units
PQ ≅ PS ≅ 7.5 units
[Since measures of tangents drawn from a point to a circle are always equal]
Perimeter of PQRS = PQ + QR + RS + PS
= 7.5 + 5 + 5 + 7.5
= 25 units
Therefore, perimeter of the quadrilateral PQRS is 25 units.