Monthly Archives: October 2024

AMC 10 Exercise – 2

Posted on October 20, 2024 by kevin

What is the tens digit of $2019^{2020}-2021$? All the numbers $2$,$3$,$4$,$5$ are assigned to the four faces of a tetrahedron. For each of the four vertices of the tetrahedron, a product of three numbers are computed, where the three numbers … Continue reading →

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Geometry Challenge – Area of Irregular Pentagon

Posted on October 15, 2024 by kevin

As shown in the diagram below, a star sign consists of five straight lines. It produces five triangles and a pentagon. If areas of five triangles are 3, 10, 7, 15, and 8 square unit respectively. Find the area of … Continue reading →

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