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Reasoning and communication abilities are two core mathematical competencies required to solve mathematical problems in mathematics and mathematics education. This research aimed to know the impact of Geogebra in learning three-dimensional geometry on students' general mathematical reasoning and communication abilities, based on their prior mathematic knowledge. Only 84 students from class XII at a high school in Central Jakarta, Indonesia, participated in this quasi-experimental study using a design randomized post-test. The research data came in six-essay-question mathematical reasoning and communication ability assessments, which were evaluated using the t-test and the Mann-Whitney test. The research findings showed that Problem-Solving with Geogebra is substantially associated with mathematical reasoning and communication abilities in geometry learning. [ABSTRACT FROM AUTHOR]

Estimating extreme rainfall conditions in spatial analysis is an important thing to do. Therefore the use of high- resolution satellites such as GSMaP is one option to be able to solve the problem. This study aims to look at the performance of GSMaP in estimating the rainfall conditions in Jakarta in the period 16 December 2019-14 January 2020 and analyze the GSMaP rainfall conditions spatially on 1 January 2020 or when floods occur in Jakarta. GSMaP data (spatial resolution: 0.1° or 10 km) was validated using observational rainfall data from BMKG with daily temporal resolution. Statistically, GSMaP's performance in estimating rainfall conditions has proven to be good. This is because the R2 and R values of the GSMaP data in Tanjung Priok and Kemayoran compared to the observation data have a value of more than 0.5. R2 values for Kemayoran and Tanjung Priok were 0.7268 and 0.7245, respectively. The error value between GSMaP data and observation data in both places calculated using RMSE, Bias Error, and Nash-sutcliffe coefficient also shows that GSMaP performance in estimating rainfall is quite good. The POD and FAR values in Kemayoran show respectively 91.30% and 16% which means that GSMaP is quite good in estimating rain events and the percentage of false alarm events is only around 16%. Meanwhile POD and FAR in Tanjung Priok were 91.67% and 12%, respectively. Spatial mapping of rainfall data GSMaP states that the West Jakarta area tends to experience very high rainfall on January 1, 2020. [ABSTRACT FROM AUTHOR]