Geometry
quadrilateral abcd has diagonals that are congruent and perpendicular to each other. what classification can be given to abcd?
a. parallelogram
b. rectangle
c. rhombus
d. square
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For which of the following counts would a binomial probability model not be reasonable? a)the number of people in a classroom born in januaryb) the number of people in a classroom with red hair c) the number of people admitted to a hospital in a day with a particular disease d) the number of heart beats in a one-minute perio.

Landon wrote that 3−2.6=4. which statement about his answer is true?

Bob the builder is making 480kg of cement mix. this is made by cement, sand and gravel in the ratio 1: 3: 4